JPH0139972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric melting furnace that applies electricity directly to the molten glass itself, melts a batch of raw glass by the heat of the molten glass, and homogenizes and clears the molten glass. The present invention relates to such an electric melting furnace that spins glass fibers directly without passing them through risers and feeders.

Glass products, such as glass fibers, are produced industrially by melting and clarifying powdered raw material glass batches with flame in an open hearth melting furnace made of a refractory material, and guiding the molten glass through a channel to a forehearth made of a refractory material. It is manufactured by spinning a plurality of platinum bushings arranged at the bottom of the fabric while conditioning and controlling the temperature by resistive heat generation by energizing the constituent platinum material (for example, (See Special Publication No. 39-5219 and Publication No. 46-34941).

In contrast to such a melting, fining, and forming system consisting of an open hearth melting furnace and a steel melting furnace, a vertical electric melting furnace has recently been developed. In this vertical electric melting furnace, the electrodes are appropriately placed relatively at the upper part of the furnace, and when electricity is applied directly to the molten glass in the furnace, an appropriate vertical temperature distribution is generated in the molten glass, and at the same time, the electrodes are placed in the upper part of the furnace. The relatively high temperature, low density molten glass is difficult to mix into the relatively low temperature, high density molten glass region below, even against the force of gravity. The heating convection area is
On the other hand, it is based on the simple principle that a laminar clear region of molten glass is formed relatively below. In this way, the electric melting furnace naturally and functionally achieves melting, stirring, and diffusion of glass batches in the same furnace, and achieves homogeneous melting near the bottom of the furnace.
It has a clear melting theory and a simple process that are not found in conventional open hearth systems that produce clarified molten glass, and thus achieves miniaturization of equipment and improved thermal efficiency. The use of electrical energy used to be expensive compared to fossil fuels even when efficiency was taken into account, but the simplicity and high efficiency of the process in electric melting furnaces, combined with the recent rise in the price of fossil fuels, has given rise to its advantages. It is gradually improving its properties and establishing itself as a new glass melting technology.

As such an electric melting furnace, for example,
Publication No. 26884 generates thermal energy by energizing the molten glass at at least two levels in at least one melting zone in the upper part of a melting tank, such that the levels are opposite in direction. An electric melting furnace and method is disclosed having a three-phase AC electrode arrangement that creates and maintains a circulating flow of molten glass.

In addition, Japanese Patent Application Laid-Open No. 47-13618 discloses that in a glass electric melting furnace having electrode groups on multiple planes in the furnace, the inner end of the electrode group on one plane is connected between the ends of the electrode groups on the plane above and below. an electric melting furnace located in the gap, thus causing the ascending glass stream of each lower plane to meet the descending glass stream of each upper plane at the interface with the upper plane, and preventing each glass stream from penetrating into the other plane; and a melting method.

Furthermore, Japanese Patent Publication No. 56-9455 discloses a method for minimizing convection of unmelted glass batches or incompletely melted glass batches deposited on molten glass in an electric melting furnace toward the furnace wall near the electrodes. , above an electrode that is immersed in molten glass,
Moreover, an electric melting furnace is disclosed in which a batch baffle plate means is attached to the furnace wall at a position where it does not come into contact with the molten glass.

Conventional electric melting furnaces, including these publications, have in common that their horizontal cross-sectional shape is a regular 3n square with n = 2 or more, usually a hexagon to a dodecagon, and typically a hexagon. . For example, the above-mentioned special public service
No. 26884 discloses a furnace structure consisting of a hexagonal upper vertical part and an inverted hexagonal pyramidal funnel-shaped bottom part connected thereto, and also discloses a furnace structure consisting of a hexagonal upper vertical part and an inverted hexagonal pyramidal funnel-shaped bottom part, and
56-9455 both disclose hexagonal prism structures.

Glass melting furnaces require temperatures of over 1,000 degrees to melt glass batches, so they are constructed of refractory materials such as refractory bricks that can withstand such temperatures. Corrosion caused by glass cannot be avoided, and its service life is only 2 to 3 years.
It is said to be around 20 years old. At the end of their useful life, furnaces are refurbished or newly built, and the cost of the furnace represents a significant portion of the cost of producing glass products. On the other hand, corrosion of fireproof materials by molten glass is not a practical problem in the early stages of operation;
The safe operation of the furnace becomes a major problem as it approaches the latter stages of operation. Therefore, the simplicity of the furnace form and the stability of the furnace structure not only guarantee the ease of furnace construction, support and reinforcement work for the furnace, but also increase the durability of the furnace and ensure the operational safety of the furnace. It is also an important factor in meaning. When considering conventional electric melting furnaces from these viewpoints, the polygonal shape increases the technical difficulty of furnace construction, makes external support and reinforcement work complicated and difficult, and makes it difficult to use refractory materials based on the polygonal shape. The large number of joints between the two leads to an increase in the number of eroded areas where erosion by molten glass progresses more vigorously, and this, together with the fact that the depth of the furnace is several times that of an open hearth, impedes the overall structural stability of the furnace. This is a contributing factor.

Another feature common to conventional electric melting furnaces is that the melting furnace is connected to a riser or other flow path through a passage such as a throat, and is connected to a sequential forming device or even a feeder. It is used by being connected to a molding device via a molding device. For example, in the above-mentioned Japanese Patent Publication No. 52-26884, molten glass is passed through a flow path connected to a stoppered opening provided in the side wall of a funnel-shaped bottom so as to form a free surface in contact with the surrounding air. JP-A No. 47-13618 teaches that the inlet and outlet of the furnace bottom communicate with an upright glass passage (riser) through a throat, and the molten glass is sent to the molding machine through a throat. It is disclosed that the material is sent from the riser to a feeder passage or feeder, temperature controlled, and removed for molding.

This arrangement is used to refine the molten glass to be molded into the final product according to the molding conditions of each product, or to condition it to adjust the temperature and viscosity conditions, as well as to adjust the glass level related to molding pressure. However, on the other hand, such an arrangement inherently includes the following problems or contradictions.

That is, the need for additional equipment such as risers and feeders, and for refining and/or conditioning of these equipment, inevitably results in increased costs in terms of equipment and energy. This cost increase becomes more significant when the scale of production is relatively small.

In addition, in an electric melting furnace, when the homogenized and clarified glass comes into contact with the refractory material of the riser and feeder, contamination due to elution of the refractory material and glass components such as B ₂ O ₃ or There is also the problem of additional heterogeneity caused by evaporation of alkali metal oxides.

By the way, during the melting process of raw glass batches, as is well known, an equilibrium relationship exists between gas and liquid, and dissolved gas is present in the molten glass. Therefore, if the temperature is constant, changes in pressure will have a significant effect on the generation and disappearance of bubbles in the molten glass. On the other hand, in a typical vertical furnace, the molten glass generally has a depth of about 1.5 to 3 m, and a pressure difference of about 0.38 to 0.75 Kg/cm ² exists between the surface and the bottom. This is sufficient pressure to influence the generation and disappearance of the bubbles. Thus,
Lifting the molten glass through a flow path or through a riser while forming a free surface between it and the surrounding air means releasing the pressure on the glass and reintroducing air bubbles into the fined molten glass. This inherently has the paradox of bringing about the state in which it occurs.

In the production of glass fiber, the present inventor has discovered that when properly controlling the laminar flow fining conditions in a vertical electric melting furnace, the pressure of the molten glass can be released without passing the molten glass through a riser or feeder. It is possible to spin fibers directly from an electric melting furnace without any problems, and when viewed as a glass fiber spinning method, it is possible to pressurize fibers that cannot be obtained with the conventional electric melting furnace-feeder system or the conventional open hearth system. The present invention has been completed by discovering that spinning can be accomplished without the need for any additional means.

Thus, an object of the present invention is to provide a vertical electric glass melting furnace having a glass fiber spinning device directly on the bottom of the furnace, which can spin glass fiber without passing through a throat, riser, or feeder. do.

Another object of the present invention is to enable an advantageous arrangement of glass fiber spinning equipment and to provide a highly structurally stable spinning device.
An object of the present invention is to provide a vertical electric glass melting furnace having a glass fiber spinning device directly on the bottom of the furnace.

According to the invention, basically a melting convection zone for the raw glass batches has a receiving opening for the raw glass batches at the top; an opening for taking out the molten glass in the furnace bottom zone and is connected below said melting convection zone. a laminar flow clarification zone of molten glass in which the glass head of said molten convection zone is in direct acting relationship; a penetrating wall defining said zone at a location immersed in molten glass within said molten convection zone; In an electric melting furnace comprising a group of electrodes for directly applying electricity to the molten glass, the furnace includes: (a) At the lower end of the melting convection area, a shelf extending inward from the peripheral wall defining the area; (b) The laminar flow clarification zone extends vertically downward from the periphery of the tray to the furnace bottom; (c) The plurality of openings for taking out the molten glass are arranged directly perpendicular to the furnace bottom. (d) a glass fiber spinning device is disposed directly on the exit side of each of said vertical openings; and (e) said electrode group is disposed on at least one horizontal level only in said melt convection area, while The laminar flow clarification zone is characterized in that no heating means is provided, especially in the process of homogenizing and clarifying the molten glass in the laminar flow clarification zone, which is necessary for direct spinning of glass fibers. For direct spinning of glass fibers, sufficient retention of the molten glass in the area and natural heat dissipation from the area are achieved to simultaneously satisfy the homogeneity and clearness of the molten glass and the temperature-viscosity conditions necessary for its spinning. An electric melting furnace is provided.

According to the electric melting furnace of the present invention, the molten glass melted, homogenized, and clarified in the melting furnace is supplied directly to the spinning device connected to the bottom opening of the furnace without passing through the riser and the feeder, can be spun into glass fibers, thus solving the technical and economical problems and inconsistencies of conventional electric melting furnace forming, as well as supplying molten glass under pressure in the melting furnace directly to the forming equipment. achieves pressure forming without the need for any pressure means. This pressure forming, especially pressure spinning of glass fibers, is carried out in the orifice plate or nozzle plate of the spinning device. The characteristics are significantly improved and improved, and thus the orifice or nozzle becomes closer together, the spinning apparatus becomes smaller, and the electric melting furnace itself becomes smaller.
Enables high efficiency.

As a particularly preferred embodiment of the present invention, in the electric melting furnace for directly spinning glass fibers of the present invention, each horizontal cross-sectional shape of the melting convection zone and the laminar flow clarification zone is formed into a rectangular shape. provides an electric melting furnace for direct spinning of

According to this preferred embodiment, an economical arrangement of a plurality of spinning devices in the electric melting furnace and an effective arrangement to facilitate the spinning operation are possible, and the rectangular cross-sectional structure facilitates the construction of the furnace and its support and reinforcement work. This also reduces joints between refractory materials where erosion by molten glass is more severe, thus significantly improving the overall structural stability of the furnace. In addition, suitable natural heat dissipation for good conditioning of the molten glass in the furnace is achieved.

The present invention described above will be further explained with reference to the accompanying drawings. However, the illustrated electric melting furnace is a preferred embodiment of the present invention, and it goes without saying that the present invention is not limited thereto.

In the accompanying drawings, FIGS. 1 and 2 relate to an electric melting furnace with a forming device according to the present invention, and FIG. 1 is a front longitudinal sectional view thereof, and FIG. are shown respectively.

In these figures, an electric melting furnace 1 consists of a melting convection zone 2 for molten glass constituting its upper part and a laminar flow fining zone 3 for molten glass constituting its lower part, and in the melting convection zone 2, an electric current is applied to the molten glass. An electrode 4 is provided for this purpose.

The melting convection zone 2 is defined by a peripheral wall 5 made of refractory bricks, at the lower end of which a shelf 6 extends inward from the peripheral wall, the top of which receives raw glass batches and is placed inside the furnace. It is fully opened to form a deposited layer 8 of glass batches on top of the molten glass 7. Although not shown, a feeding device for raw glass batches is disposed above the top opening, and the glass batches are continuously or intermittently fed into the opening, preferably by being dispersed. The size of this melting convection zone 2 depends primarily on the throughput of the raw glass batch, but can be selected from customary design values for known vertical electric melting.

In this melting convection zone 2, the glass batch is melted and to some extent clarified and homogenized under thermal convection. In addition, the tray 6 regulates the return flow of the molten glass along the peripheral wall 5, prevents the contaminated glass from entering the laminar flow clarification zone, and as a result imparts homogenization and clarification functions to the laminar flow clarification zone 3. The desirable result is to relatively increase the area of the upper melt convection zone 2 while still providing sufficient area to maintain the melting rate, thus relatively increasing the melting amount of the glass batch and reducing the furnace temperature slightly.

On the other hand, the laminar flow clarification zone 3 is defined by a peripheral wall 9 and a hearth bottom wall 10, which are also made of firebrick and are connected and extend vertically downward from the periphery of the tray 6. In this laminar flow clearing zone 3, the melting convection zone 2
The molten glass continuously fed from the molten glass is substantially completely homogenized and refined.

In the laminar flow clarification zone 3, its cross-sectional area must be at least large enough to allow the molten glass to maintain a laminar flow state and flow toward the bottom of the furnace. The cross-sectional area required to maintain this laminar flow condition depends on the amount of molten glass withdrawn for direct forming from the furnace bottom and is therefore relative. In such cross-sectional areas, it is preferred for direct molding that the laminar flow clarification zone 3 has a cross-sectional area ratio of about 0.3 to 0.9 times to the melt convection zone 2, and a cross-sectional area ratio of about 0.5 to 0.9 times. is particularly preferred. This cross-sectional area ratio is such that as long as the dimensions of the molten convection zone 2 are selected from the range of commonly used design values, the molten glass in this zone can maintain the laminar flow state even when the amount of molten glass drawn out from the furnace bottom is considered. is of sufficient value. Further, in this laminar flow clearing zone 3, the depth preferably has a value of about 0.4 to 1.0 times the maximum width of the laminar flow clearing zone, and preferably has a value of about 0.5 to 0.7 times the maximum width of the laminar flow clearing zone. More preferred. These cross-sectional areas and depths primarily regulate the residence time of the molten glass in this area and the amount of heat dissipated from the furnace walls, but the combination of the above-mentioned values of cross-sectional areas and depths is important for the homogenization and fining that takes place in this area. In the process, while maintaining the laminar flow state in the molten glass,
Achieving a homogeneous and clear state of molten glass suitable for direct molding using the electric melting furnace of this invention, and at the same time ensuring particularly well the necessary and sufficient residence time and amount of heat dissipation to satisfy the temperature-viscosity conditions necessary for molding. .

At least one, and generally a plurality of vertical openings 11 are formed in the bottom wall 10, each of which is fitted with a bushing 12 for directly spinning glass fibers 15 therein. The total amount of yarn spun by these bushings should be such that it does not disturb the laminar flow state of the molten glass in the laminar flow clarifying zone. The bushing 12 can be the same as in the case of the open hearth type, and its attachment can also be carried out by applying the means of the open hearth type.

The vertical opening 11 is provided with a molten glass guide part 13 that surrounds the inlet and protrudes from the bottom of the furnace into the furnace, so that the molten glass contaminated with eluted refractory materials flowing down along the peripheral wall of the furnace can be removed. Direct opening 11
It is preferable to prevent it from flowing into the bushing 12 from the outside. This guide part 13 can be constructed of a corrosion-resistant and fire-resistant material, but other means can be used, for example, by extending the platinum alloy plate constituting the bushing wall and by extending the opening 1.
It can also be formed by protruding into the furnace from 1. Further, the guide portion 1 made of the above-mentioned corrosion-resistant and fire-resistant material
3. It is also possible to extend and cover the platinum alloy plate of the bushing. On the other hand, deposits such as contaminated glass and eluted refractory materials can be successively removed from a drain port 14 formed approximately in the center of the furnace bottom 10.

The illustrated electric melting furnace 1 shows a melting furnace having a rectangular cross-sectional structure. In this rectangular furnace, its cross-sectional shape can be rectangular or square. When taking a rectangular cross-sectional shape, the ratio of the length of the short side to the long side can vary considerably, for example, the short side is 1/3 of the long side.
Or it can be less than that. This is because the electrical conductivity of the molten glass to which electricity is applied varies considerably depending on the glass composition. In the case of such a rectangular furnace, the depth of the laminar flow clarification zone is approximately 0.4 to 1.0 times, preferably approximately 0.4 to 0.7 times, the long side (including the case where both sides are equal) according to the above regulations. is desirable. Such a rectangular cross-sectional structure is advantageous from the viewpoint of good conditioning of the molten glass based on heat dissipation, ease of furnace construction, support and reinforcement, improvement of the structural stability of the furnace, and also from the viewpoint of the arrangement of spinning equipment. This is recommended as a particularly preferred embodiment, but the present invention does not apply to the conventional n=
This does not exclude the adoption of a structure of two or more regular 3n polygons.

In the electric melting furnace of the present invention including this rectangular furnace, the shelves 6 are generally formed on the entire circumferential surface of the peripheral wall 5, but in some cases, the peripheral wall 5 to which electrodes are attached
can only be formed. For example, in a rectangular furnace, trays 6 are formed only on one set of opposing peripheral walls, and electrodes are arranged on the peripheral walls, while the other opposing peripheral wall 5 without trays is the peripheral wall 9 of the laminar flow clarification zone 3.
It can be formed continuously. The extension width of these trays 6 preferably has a value determined by the cross-sectional area ratio of the melting convection zone and the laminar flow clarification zone. This shelf width is a preferable value for regulating the return flow of molten glass along the peripheral wall 5, which will be described later.

In the electric melting furnace 1 of the present invention, the electrode group 4 is arranged only in the melting convection zone 2 at a position where it is immersed in the molten glass therein. Electricity is applied directly to the molten glass in the furnace through these electrode groups 4, and the generated Joule heat sequentially melts and vitrifies the glass batches in the glass batch layer 8 on the molten glass at the contact interface with the molten glass, and heats the molten glass. cause convection. As is well known, by properly arranging these electrode groups 4, a convection region is formed in the molten glass in the furnace above the furnace, and a laminar flow region is formed below the furnace. These two regions correspond respectively to the melt convection zone 2 and the laminar flow clarification zone 3 of the electric melting furnace 1.

The electrode group 4 is penetrated and arranged in the peripheral wall 5 in at least one horizontal level in accordance with conventional methods, but in particular in the case of rectangular furnaces it is not necessary to arrange it on the entire peripheral wall;
They may be provided only on one set of opposing peripheral walls. Although the figure shows an example in which electrodes are arranged on the opposing short side peripheral walls, in the case of a medium-sized or large rectangular furnace, it is preferable to arrange the electrodes on the long side peripheral walls. Further, when the electrodes are disposed on the opposing wall in this manner, it is preferable that the electrodes be disposed line-symmetrically. The electrode may be either a rod-shaped electrode or a plate-shaped electrode. Although it is normal and preferable to use a three-phase power source with an RST phase as the power source, it is particularly preferable to use a single-phase power source in the case of a small rectangular furnace.

In the electric melting furnace of the present invention, the laminar flow clarification zone 3
does not have any heating means, and thus the homogenization and clarification of the molten glass necessary for spinning in this zone is achieved essentially only in the presence of the withdrawal flow of the molten glass from the vertical opening 11 in the furnace bottom 10. In addition, the molding temperature-viscosity conditions are achieved by natural heat radiation based on heat conduction from the peripheral wall 9.

In the electric melting furnace of the present invention, raw glass batches are dispersed and supplied to the open top of the furnace, and are deposited on the molten glass 7 in the furnace to form a batch layer 8. This batch layer 8 blocks heat radiation from the molten glass in the furnace. The glass batches of the layer 8 are successively heated at the contact surface with the molten glass by direct current flow from the electrode 4, and are gradually melted and vitrified by the high temperature heat. Most of the decomposition gas generated by the vitrification reaction at this time escapes through the batch layer and dissipates into the atmosphere.

The crude molten glass produced by vitrification is entrained in a vigorous circulating flow A of molten glass present in the molten glass in the melting convection zone 2 and circulates. This circulating flow A is a thermal convection of the molten glass caused by heating by the electrode 4. Due to this convection and circulation, the heterogeneous portion of the glass is stretched, and homogeneous mixing progresses through physical mixing and diffusion.
During this circulation, residual gas that has not been defoamed near the batch layer is floated and degassed.

The molten glass in this melt convection zone 2 generally has a return stream B of relatively contaminated unfined glass that also descends along the furnace wall. This return flow is likely to invade the laminar flow clarification zone 3, disturbing the laminar flow state and risking re-contaminating the homogeneous and clarified molten glass. In the present invention, this return flow B is reversed by a tray 6 provided at the lower end of the melting convection zone 2, returned to the main circulating flow A, and subjected to homogeneous mixing. Regarding this reversal of the return flow, the predetermined shelf width is a preferable value that enables this reversal.

The glass melted and mixed in this melting convection zone 2 is clarified to a considerable extent;
However, there are still some bubbles, non-uniform striae, and temperature unevenness, and it is still in an unfinished state. The unfinished glass then passes successively into the laminar flow fining zone 3, during which time it reaches the bottom of the furnace, where perfect homogeneity, temperature-viscosity conditions necessary for fining and spinning are achieved.

That is, in the molten glass in the laminar flow clarification zone 3, there is only a very slow laminar flow C flowing downward based on the amount of glass drawn out for spinning, which is sufficiently small for a large amount of molten glass. There is. The molten glass from the molten convection zone 2 rides this laminar flow C and stays in the laminar flow clarification zone 3 for a long time, and while moving downward, it is cooled only by natural heat radiation from the furnace wall based on diffusion and heat conduction. Homogeneous areas and temperature unevenness are eliminated, and at the same time a natural temperature drop occurs to achieve the temperature-viscosity conditions necessary for spinning. In addition, among the small bubbles remaining in the molten glass from the melting convection zone 2, the lamp equation V = g・d ² ρ/12η (where, V is the flow velocity of the laminar flow C, and g is the gravity is the acceleration, d is the diameter of the bubble, ρ is the density of the molten glass, and η is the viscosity of the molten glass). On the other hand, smaller bubbles are subjected to increasing pressure as the glass moves downward, and most of them dissolve into the glass according to the law of gas-liquid equilibrium. In fact, it has been found that there are virtually no air bubbles in the molten glass at the bottom of the furnace. Thus,
Near the bottom of the furnace, there is a chemically and thermally uniform
There is a bubble-free, substantially completely homogeneous, clarified, pressurized molten glass. This pressurized molten glass has a pressure equivalent to the liquid depth of the molten glass in the furnace, but when adopting the size of a vertical furnace commonly used in industry, the pressure is approximately 0.4
~0.8Kg/ ^cm2 .

According to the present invention, this pressurized molten glass is directly spun into glass fibers by a spinning device attached to the bottom of the furnace, but the pressure is applied to the orifice in the orifice plate of the bushing or the tip nozzle plate. Significantly improves and increases the outflow of the molten glass through the tip nozzle, as well as the separation properties of the molten glass cone formed at the outlet of the orifice or tip nozzle, i.e. the molten glass flowing out of the orifice or tip nozzle wets the plate material and spills over. It significantly improves the properties of forming independent cones without the need for glass fibers and facilitates the formation of glass fibers. This improvement in the separation properties of the cone also allows for closer and more dense orifices or tip nozzles.

Next, an example of direct spinning of glass fiber using the vertical electric melting furnace of the present invention will be shown by way of example. However, it goes without saying that the present invention is not limited to this example.

Example: Two pairs of molybdenum plate electrodes of 200 x 250 x 10 mm are connected to a single-phase power source above the furnace wall on the opposite short sides, and are arranged symmetrically. Equipped with a basic 800-hole bushing,
A refractory brick with a drain port approximately in the center of the hearth bottom and having the following dimensions: Melt convection area: 1600mm length x 600mm width x 720mm depth Shelf Step width: 200mm Laminar flow clarification area: 1400mm length x 400mm width x 600mm depth A batch of C-glass with an alkali metal oxide content of 7.5% by weight was melted, homogenized, and clarified using an electric melting furnace consisting of the following: and pressure-spun directly from the bushing. Glass fibers could be produced very well by this pressure spinning. The furnace conditions and spinning conditions are as follows.

Furnace temperature: 1410℃ in the center of the melting convection area Center of laminar clear zone 1280℃ Bushing introduction part 1260℃ Energy used: 1.6KWH/Kg - Glass Spinning conditions: Bushing temperature 1200℃ Winding speed 1600m/min Fiber diameter 14μ

[Brief explanation of drawings]

FIG. 1 shows an electric melting machine having a rectangular cross-sectional structure according to the present invention, which has electrodes disposed line-symmetrically on the opposite short sides of the furnace wall and a bushing for spinning glass fibers at the bottom of the furnace. A front longitudinal cross-sectional view of the furnace is shown, and FIG. 2 is a cross-sectional view taken along the plane of FIG. 1...Electric melting furnace, 2...Melting convection area, 3...
... Laminar flow clearing area, 4 ... Electrode, 5, 9 ... Peripheral wall,
6... Shelf, 7... Molten glass, 8... Glass batch deposited layer, 10... Furnace bottom wall, 11... Vertical opening, 12... Bushing, 13... Guide part, 14
...Drain port, 15... Glass fiber, A... Circulating flow of molten glass, B... Return flow of molten glass,
C... Drawing flow of molten glass.

Claims (1)

[Scope of Claims] 1. A convection area for melting raw glass batches having an opening for receiving the raw glass batches at the top; having an opening for taking out the molten glass in the bottom area and connected to the lower part of the convection area for receiving the raw glass batches; a laminar flow clarification zone of the molten glass in which the glass head of the convection zone is in direct working relationship; a laminar flow clarification zone of the molten glass in which the glass head of the convection zone is in direct working relationship; (b) At the lower end of the melting convection area, a shelf extends inward from the peripheral wall defining the area. (b) The laminar flow clarification zone extends vertically downward from the periphery of the tray to the furnace bottom; (c) A plurality of the openings for taking out the molten glass are formed directly perpendicular to the furnace bottom; ( d) a glass fiber spinning device is disposed directly on the exit side of each of said vertical openings; and (e) said electrode group is disposed on at least one horizontal level only in said melt convection zone, while said Homogenization of the molten glass, especially in the laminar flow clarification zone, characterized in that the zone is not equipped with any heating means, homogeneity of the molten glass required for direct spinning of glass fibers during the clarification process , an electric melting furnace for direct spinning of glass fibers, which achieves retention of sufficient molten glass in said zone and natural heat dissipation from said zone to simultaneously satisfy the fining state and the temperature-viscosity conditions necessary for its spinning. 2. Claim 1, wherein the cross-sectional area of the laminar flow clarification zone is 0.3 to 0.9 times the cross-sectional area of the melt convection zone, and the depth of the laminar flow clarification zone is 0.4 to 1.0 times its maximum width. Electric melting furnace described in. 3. The cross-sectional area of the laminar flow clarification zone is 0.5 to 0.9 times the cross-sectional area of the melt convection zone, and the depth of the laminar flow clarification zone is 0.5 to 0.7 times its maximum width. Electric melting furnace described in. 4. The electric melting furnace according to any one of claims 1 to 3, wherein the cross-sectional shape of the furnace is rectangular. 5. The electric melting furnace according to claim 4, wherein the electrode groups are disposed line-symmetrically on a pair of opposing peripheral walls of the furnace. 6. Any one of claims 1 to 5 above, wherein a molten glass guide part is formed in the vertical opening formed in the furnace bottom, surrounding the inlet and protruding from the furnace bottom toward the inside of the furnace. The electric melting furnace according to item 1. 7. Claim 1, wherein a drain port for drawing out contaminated glass is formed approximately at the center of the furnace bottom.
The electric melting furnace according to any one of Items 6 to 6.