JP4924979B2 - Float plate glass manufacturing apparatus and manufacturing method - Google Patents

Description

The present invention relates to a manufacturing apparatus and a manufacturing method of a float plate glass manufactured by a float process.

  An apparatus for producing plate glass by the float process is to continuously supply molten glass on a molten metal such as molten tin accommodated in a bathtub so as to float on the molten metal. At this time, an equilibrium thickness corresponding to its own surface tension is obtained. A strip of flat glass that has reached a certain thickness (about 7 mm) or is about to reach an equilibrium thickness or that is above the equilibrium thickness is pulled toward a slow cooling layer adjacent to the outlet of the bathtub. It is a device to manufacture.

  Incidentally, Patent Document 1 discloses a manufacturing apparatus suitable for a thin glass plate having a thickness of, for example, 0.1 to 1.1 mm, such as a flat panel display (FPD) plate glass. This manufacturing apparatus forms a recess in the bath surface of the molten metal along both edge portions of the molten glass ribbon, and while the both edge portions flow into and hold the recess, that is, narrow in the width direction of the molten glass ribbon. It is formed into a predetermined thin glass while compensating for the force to be wrapped.

This manufacturing apparatus includes a rod-shaped body having a longitudinal channel and a lateral channel, and a linear motor that applies a driving force to the molten metal, as means for forming the concave portion on the bath surface of the molten metal. . The rod-shaped body is installed on the hearth of the bathtub, and the linear motor is installed below the bathtub, and the moving magnetic field of the linear motor is applied to the molten metal in the lateral flow path of the rod-shaped body, The recessed portion is formed above the longitudinal flow path by sucking molten metal in the directional flow path in a substantially vertical direction with respect to the bath surface.
Japanese Patent Laid-Open No. 10-236832

  However, the float sheet glass manufacturing apparatus disclosed in Patent Document 1 and the like has a saddle that is installed in a bathtub and serves as a flow path for molten tin, and by the thermal deformation of a bottom brick that constitutes the hearth of the bathtub. There may be a gap between the bottom surface of the lateral flow path of the shaped body and the bottom brick. When such a gap is generated, the molten metal present in the gap is driven by the linear motor, which causes a problem that the molten metal in the lateral flow path cannot be driven efficiently.

  Further, in the case of a manufacturing apparatus in which a bowl is configured such that the molten metal in the lateral flow path of the bowl contacts the bottom brick, the gap is introduced from the outside of the horizontal path into the lateral flow path. Molten metal enters through the. For this reason, similarly, the problem that the molten metal in a horizontal flow path cannot be driven efficiently arises.

  Further, even when the saddle-like body and the bottom brick are in strong contact with each other due to the thermal deformation, and the lateral flow path of the saddle-like body is damaged, the inside of the lateral flow path from the outside of the lateral flow path through the damaged portion. Since the molten metal intrudes, the problem arises that the molten metal in the lateral flow path cannot be driven efficiently. As a result of such problems, it has been difficult to form a stable recess on the molten metal bath surface in the conventional manufacturing apparatus.

This invention is made | formed in view of such a situation, and can form the stable recessed part in the bath surface of a molten metal by driving the molten metal in the horizontal flow path of a bowl-shaped body efficiently. An object of the present invention is to provide a manufacturing apparatus and a manufacturing method for a float glass sheet.

  In order to achieve the above object, the invention according to claim 1 continuously supplies molten glass to a molten metal bath surface accommodated in a bathtub to form a molten glass ribbon, and advances the molten glass ribbon. And a vertical flow path that is installed in the bathtub and sucks the molten metal in a substantially vertical direction along the edge of the molten glass ribbon. In an apparatus for producing a float glass comprising a bowl-shaped body comprising a lateral channel for flowing molten metal sucked from a directional channel in an outer direction and a horizontal direction of an edge of a molten glass ribbon, The bottom surface is positioned with a gap at a predetermined interval from the bottom brick that constitutes the hearth of the bathtub, and the molten metal is prevented from entering the gap from the periphery of the lateral channel to the lateral channel side. The float member for is located to provide an apparatus for manufacturing a float glass according to claim.

According to the first aspect of the invention, the bottom surface of the bowl-like body is located on the bottom brick constituting the hearth of the bathtub, and is immersed in the bathtub in a so-called edge-cut state. In this arrangement, a gap with a predetermined interval is intentionally provided between the bottom surface of the bowl and the bottom brick, and a floating member is disposed in the gap and the gap is closed by the floating member. This prevents the molten metal from entering the lateral flow path side from the periphery of the horizontal flow path of the rod-shaped body. As a result, even if the rod-like body and the bottom brick are thermally deformed, a gap is originally set between the bottom surface of the rod-like body and the bottom brick, and this gap increases or decreases within the range of the assumption of the heat deformation. However, the gap is reliably closed by the floating member that floats. Therefore, the float glass manufacturing apparatus according to the first aspect can efficiently drive the molten metal in the lateral flow path of the bowl-like body, so that a stable recess can be formed on the bath surface of the molten metal.

  In the case of a bowl-shaped body configured such that the molten metal in the lateral flow path flows in contact with the bottom brick, the “lateral flow path side” described in claim 1 In the case of a bowl-shaped body configured such that the molten metal in the lateral flow path does not contact the bottom brick, “the lateral flow path (34) and the bottom brick” (50) ”(see FIG. 5).

  Further, the floating member described in claim 1 can be made of any material as long as it has a specific gravity lighter than that of the molten metal and can be used chemically and stably with respect to the molten metal. For example, when molten tin is used as the molten metal, examples of the material of the floating member include carbon, ceramics, and refractory bricks. Further, the floating member may be solid or hollow.

  A second aspect of the present invention is characterized in that, in the first aspect, the saddle-shaped body is configured such that the molten metal in the lateral flow path flows in contact with the bottom brick.

  The invention described in claim 2 is particularly directed to a manufacturing apparatus (see FIG. 4) configured such that the molten metal in the lateral flow path of the bowl-shaped body flows in contact with the bottom brick. Therefore, the configuration of the bowl-shaped body is relatively simple, and the gap is closed by the floating member, so that the molten metal can enter the lateral channel from the outside of the lateral channel through the gap. Can be prevented.

A third aspect of the present invention is characterized in that, in the first or second aspect, the gap is set to 2 to 20 mm .

According to the third aspect of the present invention, the lower limit of the gap at which the hook and the bottom brick are not damaged by the thermal deformation of the hook and the bottom brick is 2 mm, and the upper limit of the gap If it exceeds 20 mm, the gap becomes large, and it may be difficult for the floating member to close the gap. Therefore, the gap is preferably set to 2 to 20 mm, and more preferably set to 5 to 15 mm in consideration of the safety factor.

  A fourth aspect of the present invention is characterized in that, in the first, second, or third aspect, the floating member disposed in the gap is housed in a groove formed in the bottom brick.

  According to invention of Claim 4, a groove | channel is formed in a bottom brick, a floating member is arrange | positioned in this groove | channel, a floating member floats and sinks in a groove | channel, and closes a clearance gap. Therefore, the floating member closes the gap without coming out of the gap. FIG. 6 shows the groove 60, the gap 56, and the dimension a thereof. That is, the size (dimension) of the gap refers to the distance between the bottom brick surface and the bottom surface of the bowl.

  A fifth aspect of the present invention is characterized in that, in the fourth aspect, the floating member is formed of a substantially cylindrical rod-shaped body, and the groove is formed in a concave cross section.

  According to the fifth aspect of the present invention, since the floating member is formed of a substantially cylindrical rod-like body and the groove is formed in a concave cross section, the negative generated due to the molten metal being driven on the lateral flow path side. Due to the pressure, the floating member comes into contact at two points of the bottom surface of the bowl and the wall surface of the groove, and is pressed at these two points. Thereby, a clearance gap can be closed reliably. In addition, when the gap is set to a value exceeding 20 mm, the floating member and the groove must be processed and manufactured to a size corresponding to the floating member and the groove, so that the gap may be 20 mm or less from the viewpoint of processing man-hours and manufacturing costs. preferable.

  In order to achieve the above object, the invention according to claim 6 manufactures a float plate glass using the float plate glass manufacturing apparatus according to any one of claims 1, 2, 3, 4 or 5. A method for producing a float glass sheet is provided. According to this manufacturing method, since the stable recessed part can be formed in the bath surface of a molten metal, the thin plate glass with stable plate | board thickness can be manufactured.

  The invention according to claim 7 is the invention of the fluid circulation device, wherein the fluid is accommodated in the bathtub and the flow path body is positioned, and the fluid is passed along the lateral flow path formed in the flow path body. In the fluid circulation device that circulates in, the bottom surface of the flow path body is positioned with a gap having a predetermined interval from the bottom surface of the bathtub, and the gap extends from the periphery of the horizontal flow path into the horizontal flow path. A floating member for preventing the fluid from entering is arranged.

  Although the invention of Claims 1-6 is an invention specialized in manufacture of float plate glass, the invention of Claim 7 is not limited to manufacture of float plate glass, Claims 1-6 It is an invention of a fluid circulation device having a technical relationship that makes the specific invention the same as the described invention. That is, the invention described in claim 7 includes a bathtub that contains fluid, a flow path body, and a floating member that closes a gap between the bottom surface of the flow path body and the bottom surface of the bathtub, and the lateral direction of the flow path body The floating member prevents the fluid from entering the lateral flow path side from the periphery of the flow path.

According to the apparatus and a method for manufacturing float glass according to the present invention, the trough-like body that bottom, is positioned with a gap bottom bricks at a predetermined distance constituting a tub hearth, into this gap, gutter-like bodies Since the floating member for preventing the molten metal from entering the lateral flow channel side from the periphery of the horizontal flow channel is disposed, the molten metal in the horizontal flow channel of the rod-shaped body can be driven efficiently. Therefore, the stable recessed part can be formed in the bath surface of a molten metal.

With reference to the accompanying drawings, it will be described in detail preferred embodiments of the apparatus and a method for manufacturing float glass according to the present invention.

  FIG. 1 shows a plan view of a sheet glass manufacturing apparatus 10 that manufactures a sheet glass by a float process. The plate glass for FPD generally requires a plate thickness of about 0.1 to 1.1 mm, and also requires a high degree of flatness. The plate glass manufacturing apparatus 10 is an apparatus using a bowl-shaped body 12, and according to the plate glass manufacturing apparatus 10, it is possible to manufacture a plate glass that satisfies the plate thickness and flatness required for the FPD plate glass. .

  The rod-shaped body 12 of the plate glass manufacturing apparatus 10 is disposed inside the bathtub 14, is immersed in molten tin (molten metal) 16 accommodated in the bathtub 14, and is supplied from the molten glass furnace to the supply port 18 of the bathtub 14. It is arranged along both side edges 22 and 22 of the molten glass ribbon 20 continuously fed to. Further, the molten glass ribbon 20 advances while being pulled on the bath surface of the molten tin 16 in the direction of the slow cooling layer (X direction in FIG. 1), and the edges 22 and 22 are held in the recesses 26 of the bath surface 24. The force to narrow in the width direction of the molten glass ribbon 20 is compensated. Moreover, the molten glass ribbon 20 in which the edge 22 is held by the concave portion 26 is adjusted in plate thickness and width, and then cooled and sent to the slow cooling layer while being sent to the latter stage of the bathtub in a stable state.

  The glass of the embodiment is alkali-free glass, soda lime glass, or the like, and the molten tin 16 and the glass ribbon 20 are heated to 800 to 1300 ° C. by an electric heater (not shown).

  2 is a cross-sectional view taken along the line FF in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line GG in FIG. As shown in these drawings, the bowl-shaped body 12 is formed in a substantially L-shaped cross section, and a longitudinal channel 30 having an inlet 28 and a lateral channel 34 having an outlet 32 (see FIG. 2) and a circulation channel 38 (FIG. 3) in which a through hole 36 is formed at a position corresponding to the longitudinal channel 30.

  A linear motor 40 is installed at the bottom of the bathtub 14 and below the lateral flow path 34 of the bowl-shaped body 12, and is driven by the moving magnetic field applied from the linear motor 40 to the molten tin 16 in the lateral flow path 34. A force is applied, and the molten tin 16 flows in the direction indicated by the arrow H in the longitudinal channel 30 and the lateral channel 34 of the bowl 12.

  By this operation, a flow of the molten tin 16 is generated in a direction substantially perpendicular to the bath surface 24 and toward the bottom of the bathtub 14, so that a negative pressure is generated below the edge 22 of the molten glass ribbon 20, Due to this negative pressure, the bath surface level of the molten tin 16 in the vicinity of the edge 22 becomes lower than the surrounding bath surface level. Then, the edge 22 of the molten glass ribbon 20 flows into the recessed portion 26 of the lowered bath surface 24. As a result, the edge 22 of the molten glass ribbon 20 is held in the recess 26, so that the width of the molten glass ribbon 20 can be increased, and by being pulled in the direction of the slow cooling layer while being held in the width direction, Is produced into a thin glass plate (thickness of 0.1 to 1.1 mm).

  The material of the rod-like body 12 is not particularly limited as long as it has a low reactivity with respect to the molten tin 16, or has no reaction, and has a high temperature resistance, such as alumina, sillimanite (silicite), clay, etc. Carbon can be exemplified. In the embodiment, the linear motor 40 is used and a magnetic field is applied to the bowl-shaped body 12, so that the material of the bowl-shaped body 12 needs to be a non-magnetic material, and that the workability is good because it is large. Carbon is applied because it requires.

  The linear motor 40 has an advantage that the molten tin 16 can be directly driven in a non-contact manner and flow rate control is easy. The linear motor 40 forms a coil on a comb-shaped primary iron core, applies a three-phase AC voltage to the coil, and sequentially magnetizes the coil to generate a magnetic field that moves in a certain direction. This linear motor 40 is installed below the bottom bricks 50 covering the bottom bricks 50, 50... And the bottom bricks 50, 50. It arrange | positions in the position where a driving force (biasing force) acts with respect to a certain molten tin 16. FIG. As a result, the molten tin 16 in the vertical flow path 30 and the horizontal flow path 34 moves from directly below the edge 22 of the molten glass ribbon 20 toward the side wall 15 of the bathtub 14 as indicated by an arrow H by the driving force of the linear motor 40. Fluid.

  The rod-shaped body 12 has a circulation channel 38 in addition to the longitudinal channel 30 and the lateral channel 34. The circulation channel 38 is communicated with the bathtub central side portion 14B of the edge 22 of the molten glass ribbon 20 through a through hole 36 formed at a position corresponding to the longitudinal channel 30. 14A and the bathtub center side part 14B are connected via the flow path 38 and the through-hole 36 for a circulation. Therefore, as shown in FIGS. 2 and 3, the molten tin 16 that has flowed out from the outlet 32 of the lateral flow path 34 and whose flow direction has been changed by the side wall 15 of the bathtub 14 is partially circulated as indicated by the arrow I. 38 and led to the bathtub central side portion 14B through the through hole 36. Further, the remaining molten tin 16 flows out to the bath edge 14 </ b> A as indicated by an arrow J and is sucked into the inlet 28 of the longitudinal flow path 30.

Further, a plurality of circulation channels 38 are formed at a predetermined interval in the flow direction of the molten glass ribbon 20 as indicated by broken lines in FIG. The formation interval of the circulation flow path 38 is set at an interval that does not disturb the molten tin sucked at the inlet 28 of the longitudinal flow path 30 and an interval that does not affect the concave shape of the recess 26. The balance of the flow rates of both flowing into the inlet 28 of the longitudinal flow path 30 from the bathtub edge 14A and the bathtub central side 14B is set to an interval that is substantially uniform over the entire length of the inlet and that is optimal with respect to edge holding. . Circulation flow path, for example, may be provided for each 0.3～1M.

  Control of the outflow of the molten tin 16 may be controlled and set in advance before the operation of the plate glass manufacturing apparatus 10, or may be controlled and set while performing glass production after the operation of the plate glass manufacturing apparatus 10.

  According to the bowl-shaped body 12 configured in this way, a part of the molten tin 16 flowing out from the outlet 32 of the lateral flow path 34 of the bowl-shaped body 12 to the bathtub edge 14A is The suction force generated at 28 leads to the bathtub central side portion 14 </ b> B through the circulation channel 38 and the through hole 36, and is sucked into the inlet 28. As a result, as shown in FIG. 4, the flow rate q1 of the molten tin 16 flowing from the bathtub edge 14A to the inlet 28 and the flow rate q2 of the molten tin 16 flowing from the bathtub central side portion 14B to the inlet 28 are balanced. The flow rates of both the flow rates q1 and q2 along the traveling direction of the ribbon 20 are substantially uniform, and the concave portion 26 having a shape suitable for holding the edge on the bath surface 24 extends over the entire length of the rod-shaped body 12 and in the traveling direction of the molten glass ribbon 20. Accordingly, the entire length of the edge 22 is stably held in the recess 26. Therefore, a plate glass satisfying the plate thickness and flatness required for the FPD plate glass can be produced. FIG. 4 is a schematic diagram showing a simplified cross section of the rod-shaped body shown in FIGS. 2 and 3.

  Further, when the temperature is set for each predetermined block in the flow direction of the molten glass ribbon 20, if at least one circulation channel 38 is provided at a position corresponding to the block, The temperature distribution can be kept constant, and stable glass quality can be obtained.

  By the way, the plate glass manufacturing apparatus 10 of the embodiment is configured to efficiently drive the molten tin 16 in the lateral flow path 34 of the bowl-shaped body 12 to form a stable recess 26 on the bath surface of the molten tin 16. It has the following configuration.

That is, as shown in FIGS. 2 to 4 and FIG. 6 , the bottom surface 12 </ b> A of the bowl-shaped body 12 is positioned with a gap 56 of a predetermined gap from the bottom bricks 50, 50. A floating member 58 for preventing the molten tin 16 from entering the lateral channel 34 from the periphery of the lateral channel 34 is disposed in the gap 56.

  According to the gap closing structure with such a floating member 58, the bottom surface 12A of the bowl-like body 12 is positioned on the bottom brick 50 and is immersed in the bathtub 14 in a so-called edge cut state. In this arrangement, a gap 56 is intentionally provided between the bottom surface 12 </ b> A of the bowl-shaped body 12 and the bottom brick 50, and a floating member 58 is arranged in the gap 56 to place the gap 56. Is closed by the floating member 58. Thereby, it is possible to prevent the molten tin 16 from entering the lateral flow path 34 from the periphery of the lateral flow path 34 of the bowl-shaped body 12.

  Therefore, even if the bowl-shaped body 12 and the bottom brick 50 are thermally deformed, a gap 56 is originally set between the bottom surface 12A of the bowl-shaped body 12 and the bottom brick 50, and the gap 56 is not thermally deformed. Even if it increases or decreases within the expected range, the gap 56 can be reliably closed by the floating member 58 that floats. Therefore, since the plate glass manufacturing apparatus 10 of the embodiment can efficiently drive the molten tin 16 in the lateral flow path 34 of the bowl-shaped body 12, a stable recess 26 is formed on the bath surface of the molten tin 16. it can.

  The floating member 58 can be made of any material as long as it has a specific gravity lighter than that of the molten tin 16 and can be used chemically and stably with respect to the molten tin 16. For example, carbon, ceramics, and refractory bricks can be exemplified as the material of the floating member 58. Further, the floating member 58 may be solid or hollow.

Moreover, the clearance gap 56 is set to 2-20 mm (dimension shown by a of FIG. 6), Preferably it is set to 5-15 mm. This dimension will be described. The lower limit of the gap 56 is 2 mm so that the flange 12 and the bottom brick 50 are not damaged by the thermal deformation of the bowl 12 and the bottom brick 50. If the upper limit exceeds 20 mm, the gap 56 becomes large, and the floating member 58 may be difficult to close the gap 56. For this reason, the gap 56 is set to 2 to 20 mm, and is set to 5 to 15 mm in consideration of the safety factor.

  Further, the floating member 58 is stored in a groove 60 formed in the bottom brick 50. When the groove 60 is formed in the bottom brick 50 and the floating member 58 is placed in the groove 60 as described above, the floating member 58 floats and sinks with respect to the molten tin 16 in the groove 60 to close the gap 56. Therefore, the floating member 58 closes the gap 56 without detaching from the gap 56. A groove may also be formed on the bottom surface 12A of the bowl-shaped body 12.

  Furthermore, as shown in FIG. 6, the floating member 58 is formed of a substantially cylindrical rod-like body, and the groove 60 is formed in a concave cross section. By specifying this shape, the floating member 58 is caused at two points, that is, the bottom surface 12 </ b> A of the bowl-shaped body 12 and the wall surface 60 </ b> A of the groove 60 by the negative pressure generated when the molten tin 16 is driven in the lateral flow path 34. While contacting, it is pressed at these two points A and B. Thereby, the clearance gap 56 can be closed reliably. Further, if the gap 56 is set to a value exceeding 20 mm, the floating member 58 and the groove 60 must be processed and manufactured in a size corresponding thereto. Therefore, the gap 56 is preferably 20 mm or less from the viewpoint of processing man-hours and production costs.

  By using the plate glass manufacturing apparatus 10 configured as described above, the stable concave portion 26 can be formed on the bath surface of the molten tin 16, and thus the thin plate glass 20 having a stable plate thickness can be manufactured.

  In the embodiment, the rod-like body 12 configured such that the molten tin 16 in the lateral flow path 34 flows in contact with the bottom brick 50 has been described. However, the present invention is not limited to this, and FIG. It goes without saying that the rod-like body 12 configured so that the molten tin 16 in the lateral flow path 34 does not contact the bottom brick 50 can be applied.

  2 to 5 show that the floating member 58 is disposed so as to prevent the molten tin 16 from entering from the bathtub central side portion 14B side of the bowl-shaped body 12, The arrangement position is not limited to this. For example, when a plurality of the end portions of the bowl-shaped body 12 on the bathtub supply port 18 side or the latter-stage side of the bathtub, or the bowl-shaped body 12 are provided independently in the flow direction of the molten glass ribbon 20, the molten glass ribbon 20 The floating member 58 may be provided in parallel to the lateral flow path 34 so as to prevent the molten tin 16 entering from the flow direction side.

  Furthermore, although the said embodiment demonstrated the example specialized in manufacture of the float plate glass, the structural requirements of the specific invention which comprises the high-order concept of this invention are the bathtub, flow path body, and flow path which contain the fluid It is a floating member that closes the gap between the bottom surface of the body and the bottom surface of the bathtub and prevents fluid from entering. For this reason, the present invention can be applied to, for example, an aquarium or aquaculture water tank (fluid circulation device) having these structural requirements.

The top view which showed the manufacturing apparatus of the plate glass of embodiment Sectional drawing of the rod-shaped body seen from the FF line of FIG. Sectional drawing of the rod-shaped body seen from the GG line of FIG. Explanatory drawing which simplified the cross section of the rod-shaped body shown in FIG. 2, FIG. Explanatory drawing which simplified the cross section of the example of the bowl-shaped body comprised so that the molten tin in a horizontal flow path might not contact bottom bricks The expanded sectional view which shows the state by which the floating member was arrange | positioned in the clearance gap between the bottom face of a bowl-shaped body, and a bottom brick

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Plate glass manufacturing apparatus, 12 ... Rod-like body, 14 ... Bath, 16 ... Molten tin, 18 ... Supply port, 20 ... Molten glass ribbon, 22 ... Edge, 24 ... Bath surface, 26 ... Recessed part, 28 ... Inlet, 30 ... vertical flow path, 32 ... outlet, 34 ... lateral flow path, 36 ... through hole, 38 ... circulation flow path, 40 ... linear motor, 50 ... bottom brick, 52 ... bottom casing, 56 ... gap, 58 ... Floating member, 60 ... groove

Claims (7)

An apparatus for producing a float plate glass that continuously supplies molten glass to a molten metal bath surface contained in a bathtub to form a molten glass ribbon and advances the molten glass ribbon to form a glass plate having a target thickness. A vertical channel that is installed in the bathtub and sucks the molten metal in a substantially vertical direction along the edge of the molten glass ribbon, and the molten metal sucked from the vertical channel is outside the edge of the molten glass ribbon. In an apparatus for producing a float sheet glass comprising a bowl-shaped body composed of a lateral flow path that flows out in a horizontal direction.
The bottom surface of the bowl-like body is positioned with a gap at a predetermined interval from the bottom brick constituting the hearth of the bathtub, and in the gap, molten metal is formed from the periphery of the lateral flow path to the lateral flow path side. A float plate glass manufacturing apparatus, wherein a floating member for preventing intrusion is disposed.   The apparatus for producing a float sheet glass according to claim 1, wherein the bowl-shaped body is configured such that the molten metal in the lateral flow path flows in contact with the bottom brick. The said clearance gap is set to 2-20 mm, The manufacturing apparatus of the float glass sheet of Claim 1 or 2 characterized by the above-mentioned.   The float sheet glass manufacturing apparatus according to claim 1, wherein the floating member disposed in the gap is housed in a groove formed in the bottom brick. . The float sheet glass manufacturing apparatus according to claim 4, wherein the floating member is formed of a substantially cylindrical rod-like body, and the groove is formed in a concave cross section.

  Float plate glass is manufactured using the float plate glass manufacturing apparatus as described in any one of Claim 1, 2, 3, 4 or 5. The manufacturing method of the float plate glass characterized by the above-mentioned. In the fluid circulation device for storing the fluid in the bathtub and positioning the flow path body, and circulating the fluid in the bathtub along the lateral flow path formed in the flow path body,
The bottom surface of the flow path body is positioned with a predetermined gap from the bottom surface of the bathtub to prevent fluid from entering the horizontal flow path from the periphery of the horizontal flow path. A fluid circulation device in which a floating member is arranged.

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