JP2002121034A - Glass outflow device for glass melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass outflow device for a glass melting furnace which enables high-accuracy and high-efficiency production in running a prescribed amount of molten glass off from an outflow pipe connected to a melting crucible of optical glass. SOLUTION: This device is constituted by installing a second glass outflow pipe separated from the outflow pipe and the melting crucible in a downward direction in the outlet of the first outflow pipe connected to the melting crucible in running the prescribed amount of the molten glass off from the outflow pipe of the melting crucible of the optical glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly uses a melting crucible of an optical glass and an outflow pipe to melt and outflow a glass material when a high-precision optical glass element such as a lens or a prism is press-molded. The present invention relates to a glass outflow device in a glass melting furnace.

[0002]

2. Description of the Related Art Conventionally, an optical glass element such as a glass lens is formed by grinding and polishing a glass block having a predetermined size.
It was manufactured by processing it into a predetermined shape. However, the production of a lens having an aspherical shape requires a great deal of processing time for both grinding and polishing with a very high precision processing technique, and requires a great deal of cost.

In recent years, a heat-softened glass material is pressed in a non-oxidizing atmosphere using a mold having an aspherical shape (negative shape).
A manufacturing method for obtaining a low-cost aspherical lens has been proposed.

Further, in order to obtain an inexpensive press-formed product,
The glass material is melted in the crucible to form a highly homogeneous molten glass, and the outflow pipe connected to the crucible is temperature-controlled by external heating or direct electric heating, whereby the molten glass is dropped and flows out, A manufacturing method of receiving a predetermined amount by a receiving mold or the like and press-molding the molded product in a molding die to obtain a high-precision optical glass element (molded product) has been implemented (for example, JP-A-2-34525, JP-A-2-34525). 3-1
The production method is described in, for example, JP-B-37025).

[0005]

However, in the manufacturing method for obtaining an optical glass element (molded product) by dropping and flowing the above-mentioned molten glass and press-molding a predetermined amount thereof, an optical glass is manufactured with high precision. In addition, there are the following problems in flowing out efficiently.

[0006] Due to the thermal expansion of the pipe portion of the outflow tank, the center position deviation in the horizontal direction between the outlet portion of the outflow pipe and the glass receiving portion of the forming device, and the vertical position, due to the deformation and movement of the position. Due to displacement, poor threading, poor appearance due to uneven contact of the glass flow to the receiving mold, and variation in the weight of the glass material (glass lump) received by the receiving mold in cutting with a shear or glass cutting with a shearless, This leads to a reduction in the yield of molded products.

[0007] As a countermeasure, by equipping the receiving portion with means for adjusting the horizontal center and the vertical (height) position with respect to the outlet pipe outlet, the device is complicated.

[0008] The glass outflow amount of the outflow tank pipe is controlled by the pipe temperature (in the case of external heating and in the case of direct heating)
Can be changed only within the range, the flow rate variation is poor, and it is not suitable for multi-product / small-lot production.

Deterioration of mass productivity due to generation of weight time until temperature equilibrium due to deformation and misalignment due to temperature changes at the furnace body including the melting crucible and at the outlet of the outflow tank pipe when the furnace is started up Is inevitable.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to supply a predetermined amount of molten glass from an outflow pipe connected to a melting crucible for optical glass. An object of the present invention is to provide a glass outflow device in a glass melting furnace that enables high-precision and high-efficiency production.

[0011]

In order to achieve the above object, a glass outflow device in a glass melting furnace according to the present invention is designed to discharge a predetermined amount of molten glass from an outflow pipe of a melting crucible for optical glass. A second glass outflow pipe separated from the outflow pipe and the melting crucible is provided below the outlet of the first outflow pipe connected to the melting crucible.

As described above, by installing the second glass outflow pipe independent of the first outflow pipe, the optical glass is melted using the glass melting furnace, and when the outflow is performed, the receiving portion for the receiving portion is removed. The horizontal center position and the height position of the outflow pipe outlet are set, and the misalignment due to the difference in thermal expansion between the melting furnace main body containing the crucible and the first outflow pipe can be corrected. This eliminates the need to adjust the center position, thereby enabling reliable and stable glass outflow.

In this case, as an embodiment of the present invention, when a predetermined amount of molten glass flows out from a first outflow pipe connected to a glass melting furnace for optical glass, the outlet position of the outflow pipe is determined. Controlling the relative position of the outlet of the second outlet pipe separated from the outlet pipe, and further controlling the outlet position of the second glass outlet pipe (supporting the furnace body). It is effective that the fixed gantry is provided with means for positioning and fixing and supporting the second glass outflow pipe).

According to an embodiment of the present invention, a first outflow pipe connected to the melting crucible is provided when a predetermined amount of molten glass flow flows out of the outflow pipe of the melting crucible;
It is preferable that the flow rate of the molten glass be individually controlled by direct current heating in the outflow pipe and the separated second glass flow pipe.

As described above, when the optical glass is melted and discharged using the melting furnace, the flow rate of the molten glass flowing out of the first outflow pipe connected to the melting crucible (the control of the first outflow pipe). Glass flow rate),
By controlling the flow rate in multiple stages with the second glass outflow pipe, it is possible to supply (control) the glass outflow to the receiving portion of the glass with high precision in the forming process, and furthermore, it is possible to control the glass outflow over a wide range. It is easy to carry out and efficient glass outflow is possible.

[0016]

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a configuration diagram of a melt outflow apparatus in a continuous glass melting furnace showing a first embodiment. In FIG. 1, reference numeral 1 denotes a charging / dissolving / refining tank, 2 denotes a homogeneous / outflow tank, and 3 denotes a charging / dissolving / refining tank 1.
Connecting pipes, 4 and 5 are outflow pipes, and the components 1 to 4 are integrally formed and connected to the furnace bottom iron plate 7 (including the side wall and the top plate to surround). The furnace is surrounded by a furnace body 6 (all inner walls are heat-resistant and heat-insulating members). The outflow pipe 5 is a second outflow pipe separated from the homogeneous / outflow tank 2 and the outflow pipe 4 (first outflow pipe).

Reference numeral 16 denotes a molten glass receiving mold, and the outflow pipe 5 and the receiving mold 16 are fixed support bases 17, 1 respectively.
8 is positioned and supported.

Reference numeral 10 denotes a charging section, and 9 denotes a heater for heating, which is disposed between the components 1 to 3 and the furnace main body 6 so that a heating temperature satisfying each function can be obtained as appropriate. It has become. Further, reference numeral 8 denotes a stirring propeller,
It is provided through the furnace top plate 7 for homogenization of the outflow tank 2, and can be stirred by a drive mechanism (not shown) (the rotation direction is the direction of the arrow). Note that components 1 to 5
Each member of the stirring propeller 8 and the charging section 10 is made of platinum and a platinum alloy.

Reference numeral 12 denotes a fixed support base, and the above-described components 1-4 and 6-10
And a space for installing the components 16 to 18 in the molten glass receiving device is secured. In addition, 13 is a glass raw material, 14 is molten glass, and 15 is molten glass which has flowed out.

In the glass melting and outflow process in the continuous melting furnace, first, the glass raw material 13 introduced from the charging section 10 is melted in the charging / melting and refining tank 1, and is connected through each step. It passes through the pipe 3 and enters the homogenizing / outflow tank 2. Then, after being sufficiently homogenized by the stirring propeller 8, the molten glass 15 flows out of the outflow pipes 4 and 5 as the molten glass 15 under the optimal temperature conditions for the post-forming step.

Thereafter, the glass 15 that has flowed out is received, for example, below the outflow pipe 5 by a receiving device (not shown).
With the receiving mold 16 in, as a predetermined amount of molten glass lump,
Received. At this time, the charging unit 10 (not shown) in the charging device (not shown) allows the molten glass 15 to flow out by a certain amount.
Thus, a certain amount of the glass raw material 13
Are supplied continuously or intermittently.

The above-mentioned stirring device and receiving device can be positioned with respect to the fixed support base 12 by a positioning mechanism (not shown).

Here, a method of flowing the molten glass 15 to the receiving mold 16 below the outflow pipe 5 will be described with reference to FIG. FIG. 2 is a sketch of an outflow portion of the continuous melting furnace. Electrode terminal portions 4a and 4b for direct energization and heating are attached to the outflow pipe 4 connected in the downward direction of the above-described homogenization / outflow tank 2 by means such as welding and fixing, and a power supply portion ( The outflow pipe 4 can be appropriately heated and controlled by measuring the power supplied from an unillustrated power supply or a thermocouple (not shown).

Further, electrode terminals 5a and 5b for direct energization and heating are also attached to the outflow pipe 5 disposed below the outflow pipe 4 by means such as welding. Similarly, the power of the outflow pipe 5 can be appropriately controlled by the power supplied from the power supply unit (not shown) and the temperature measurement. Further, the electrode terminal portions 5a and 5b are fixedly supported on the fixed supports 17 and 18 via an insulating material (not shown).

Here, the positional relationship between the outflow pipes 4, 5 and the receiving mold 16 will be described below with reference to FIG. FIG.
Is a sectional view taken along AA shown in FIG.
5, the receiving mold 16 is shown in a cross section whose respective central axes are parallel to the X direction). The above-mentioned molten glass receiving mold 16
The horizontal center (X, Y directions) of the receiving die (fixed and supported by the fixed support 17 via the receiving device described above) and the center position of the outflow pipe 5, and the center height position of the receiving die The outflow pipe 5 and the receiving mold 16 are positioned and fixedly supported so that the distance h at the lower end exit height position (Z direction) of the outflow pipe 5 is kept constant.

The mouth diameter of the upper end of the outflow pipe 5 is D:_Three
Is the outlet diameter at the lower end of the outflow pipe 4: D _TwoFor D_Three>
D_Two(The outflow pipes 4 and 5
Regarding the height relation, the flow at the lower end exit of the outflow pipe 4
Lower end position of outflow pipe 4 in consideration of insulation of glass
Is set at a position lower than the upper end height of the outflow pipe 5.
Is desirable).

From the above, the furnace operation is started and stopped (heating,
During cooling, the center deviation (X, Y directions) of the exit of the outlet pipe 4 and the height of the lower end of the outlet of the outlet pipe are caused by the thermal expansion and contraction of the furnace body (components 1 to 4, 6, and 7). The molten glass 15a that has flowed out of the outflow pipe 4 is received by the outflow pipe 5 without being affected by the displacement of the height position (Z direction).
The molten glass 15b can flow out to the receiving mold 16 in the downward direction in a state where both the center of the plane and the height position are stable.

Next, using the above-mentioned continuous glass melting furnace,
The step of discharging the molten glass will be specifically described. In addition, the optical glass which has optical characteristics, such as a camera and a video camera, was used for the molten glass in this process. In addition, a multi-tank continuous melting furnace having the following general shape was used.

That is, the charging / dissolving / refining tank 1 has a rectangular parallelepiped shape, the homogeneous / outflow tank 2 has a cylindrical shape, the connecting pipe 3 has a rectangular parallelepiped shape, the outlet pipe 4 has a cylindrical shape, and the entire surface of the furnace outer wall iron plate 6 The enclosed furnace body 5 used was a rectangular parallelepiped, continuous melting furnace.

Further, each temperature data at the time of heating the multi-tank type continuous melting furnace will be described below.

Heater specification; Ceramic heater Heater in furnace; Charging / melting / refining tank 1 side; 1,200
Control temperature from ℃ to 1,500 ℃ Homogenous / outflow tank 2 side; 1,000 ℃ to 1,300 ℃ Furnace outer wall iron plate; distribution measurement temperature at temperature from 200 ℃ to 400 ℃ (measurement is the average value of three arbitrary measurement ) Measurement temperature of fixed support stand and peripheral equipment; normal temperature. Conditions for continuous glass melting furnace described above (furnace heating state)
In FIG. 3, the outflow pipe temperature and the amount of glass outflow when glass outflow was performed using the outflow pipes 4 and 5 having respective shapes and dimensions are shown in Table 1 below. The results were as follows.

Outlet pipe 4 shape dimensions; lower end mouth inner diameter: D1, lower end mouth outer diameter: D2 Outlet pipe 5 shape dimensions; upper end mouth inner diameter: D3, lower end mouth inner diameter: D4 Pipe overall length: L1, pipe taper length: L2, pipe height position (= overlap amount with pipe 4): H1, D1 = φ6mm, D2 = φ8mm, D3 = φ12mm, D4 = φ3mm, φ5mm L1 = 10mm, L2 = 5mm at room temperature , H1 = 1 mm 2.

Further, the measured temperature of the outflow pipe 4 (the middle part of the entire length of the pipe): T1, the measured temperature of the outflow pipe 5: T2, and the outflow amount of glass: Q

[0035]

[Table 1]

Under the above conditions (furnace heating state), when the glass is discharged from the multi-tank type continuous glass melting furnace, the center position accuracy and the height position of the outlet of the lower end of the discharge pipe 5 in the horizontal plane direction are measured. The accuracy was as follows. That is, the center position of the outlet at the lower end of the outflow pipe 5 and the receiving die 16 in the horizontal plane direction in each temperature state of cold (normal temperature) and hot (furnace temperature at which the glass can be melted and discharged), and , The displacement of the distance h in the height position (Z direction) was within ± 0.1 mm in both the X and Y directions, and the distance h was within ± 0.2 mm. Repeated 50 times with a non-contact line sensor).

Further, in the state after the glass melt-outflow was repeatedly performed, 100 pieces of the glass melt were continuously separated by shearless cutting using the receiving mold 16 and were molded. There was no occurrence of poor threading and poor appearance, and the weight variation was within ± 1%.

In this embodiment, the outflow pipe 5
And the receiving die 16 are respectively positioned and fixedly supported, but a system based on position measurement by a non-contact sensor and feedback position control by an automatic positioning mechanism may be used.

In this embodiment, the direct heating is used as the heating method for the outflow pipe. However, it is of course possible to use an external heating method such as a ring heater or high frequency heating as another heating method. is there.

Further, when the optical glass is melted by using a melting furnace and the outflow is performed, the outflow pipe and the second crucible separated from the melting crucible are located below the outlet of the outflow pipe in the melting crucible. When the glass outlet of the outflow pipe is installed, the following specific effects can be obtained when the molten glass flows out.

1) The horizontal center of the outlet portion and the height position of the first outflow pipe due to the difference in thermal expansion between the melting furnace body and the outflow pipe during heating and cooling are prevented, and the glass receiving portion ( Molding step) The center position adjustment with the apparatus is not required, and a reliable, highly accurate, and stable outflow of glass becomes possible. Further, a conventional device mechanism for adjusting the center position of the outlet portion of the first outflow pipe is unnecessary, and simplification of the entire device is achieved.

2) In addition, in the separated second outflow pipe, the outflow method in which the second glass flow rate is controlled in a multi-stage manner to the glass receiving portion (forming step) with high precision glass outflow and supply ( Control) is possible, and furthermore, a wide range of glass outflow control can be realized very easily (eg, by changing the opening diameter of the separated outflow pipe), and an efficient and low-cost outflow of optical glass, and , Molding becomes possible.

(Second Embodiment) FIG. 4 is a sectional view and a plan view of a tip end of an outflow pipe for explaining a second embodiment according to the present invention. Here, 19 is an outflow pipe connected directly below the melting crucible of the outflow tank 2,
Reference numeral 20 denotes an outflow pipe separated from the outflow tanks 2 and 19, and 20 is positioned and supported on a fixed support.

The power introduction section (not shown) for directly energizing and heating the respective sections of the outflow pipes 19 and 20 is the same as that of the first embodiment (all the outflow pipes and the power introduction section are also made of platinum or , A platinum alloy, and the outflow control method of the molten glass is the same.)

Here, the outlet at the lower end of the outflow pipe 19 is set at 1
9a (inner diameter: d1, outer diameter: d2), the upper end of the outflow pipe 20 is 20a (short diameter: d5, long diameter: d6), and the same pipe 2
When the lower end of 0 is 20b (short diameter: d3, long diameter: d4), the upper end 20a of the outflow pipe has a mouth diameter: d3 with respect to the outer diameter d2 of the outflow pipe 19 such that d3> d2. Is set. Regarding the height relationship between the outflow pipes 19 and 20, the lower end 19a of the outflow pipe 19 'is also taken into consideration in keeping the temperature of the outflow glass at the lower end outlet of the outflow pipe 19 in consideration.
It is desirable that the position is set at a lower end position than the height of the upper end portion 20a of the outflow pipe 20.

Next, the process of flowing out molten glass using the above-described continuous glass melting furnace will be specifically described. In addition, about the molten glass of this process, and the melting furnace, the thing of the form similar to 1st Embodiment was used. The same applies to each temperature data when the melting furnace is heated.

Further, under the conditions of the above-mentioned glass continuous melting furnace (furnace heating state), the outflow pipes 19 and 20 whose shapes and dimensions are shown in FIG. , Outflow pipe temperature and glass outflow are shown in Table 2.
The experimental results shown in FIG.

Outlet pipe 19 shape dimensions; lower end mouth inner diameter: d1, lower end mouth outer diameter: d2 Outlet pipe 20 shape dimensions: lower end short diameter: d3, lower end mouth long diameter: d4 upper end short diameter: d5, upper End base long diameter: d6 Pipe full length: 11, Pipe taper length: 12, Pipe height position (= overlap with pipe 19): h1, d1 = 4mm, d2 = 6mm, d3 = 2 mm d4 = 9 mm, d5 = 8 mm, d6 = 13 mm l1 = 15 mm, l2 = 7 mm h1 = 2 mm

Under the above conditions (furnace heating state), when the glass was discharged from the multi-tank type continuous glass melting furnace, the horizontally elongated flat molten glass flow 22 was discharged from the lower end outlet of the discharge pipe 20.
Was obtained at the outflow rate shown in Table 2.

Measured temperature of the outflow pipe 19 (middle part of the entire length of the pipe): t1, Measured temperature of the outflow pipe 20: t2, glass outflow: q

[0051]

[Table 2]

At this time, the lower end outlet of the outflow pipe 20 and the horizontal direction of the receiving mold 21 in each temperature state of cold (normal temperature) and hot (furnace temperature and pipe temperature at which glass can be melted and discharged). The deviation of the center position and the height position (Z direction) was within ± 0.1 mm in both the X and Y directions and within ± 0.2 mm in the height distance. , 50 times with a non-contact line sensor).

Further, in a state after the glass melt-outflow was repeatedly performed, 30 pieces of the horizontally long molten glass mass were continuously separated by shearless cutting using the receiving mold 21 and molded. Poor stringing, poor appearance,
There were no occurrences of optical performance defects such as striae, and weight variations were all good within ± 1%.

Further, the accuracy of the outer diameter of the horizontally long glass ingot was within ± 0.3 mm of the variation of the minor dimension and within ± 0.5 mm of the variation of the major dimension.

Here, the outlet shape of the lower end of the outflow pipe 20 is made into a horizontally long hole shape, and the horizontally elongated molten glass lump is received in a receiving mold and molded, but the outflow pipe 20 is formed by using a mechanical drive control device. It is, of course, also possible to form a horizontally long glass block by moving it in the horizontal direction (the receiving die is only driven in the vertical direction) (otherwise, up, down, left, right, straight,
If various types of mechanical drive control devices are used irrespective of the non-linear shape, it is also possible to freely move the second outflow pipe to form a molten glass lump having a different shape.)

In this embodiment, when the optical glass is melted by using a melting furnace and the melted glass is discharged, the outflow pipe, the outflow pipe separated from the melting crucible and the outflow pipe separated from the outflow pipe outlet of the melting crucible are positioned below. The following specific effects can be obtained when the glass flows out with a molten glass apparatus provided with a glass outlet.

In the separated outflow pipe, a high-precision and wide-ranging glass outflow control (the formation of irregularly shaped glass blocks) to the receiving portion (forming step) of the glass is performed by the outflow method in which the second glass flow rate is controlled in multiple stages. Outflow supply, etc.) can be performed very easily, and efficient and low-cost outflow and molding of optical glass can be performed in producing an optical glass element.

[0058]

As described above, according to the present invention,
By placing the outflow pipe and the second glass outflow pipe separated from the melting crucible below the outlet of the first outflow pipe connected to the melting crucible, high precision and high efficiency production can be achieved. .

In particular, in the present invention, by controlling the outlet position of the second outflow pipe with respect to the outlet position of the first outflow pipe connected to the melting crucible, high precision and high efficiency production can be achieved. it can.

Further, according to the present invention, the first outflow pipe connected to the melting crucible and the glass outflow port of the second outflow pipe are made of platinum or a platinum alloy, and are made of molten glass by direct electric heating. By individually controlling the flow rates of the above, high-precision and high-efficiency production can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic side view for explaining a forming apparatus used in a glass outflow method according to an embodiment of the present invention.

FIG. 2 is a schematic plan view for explaining a forming apparatus used in the outflow method of the glass melting furnace in the first embodiment according to the present invention.

FIG. 3 is a schematic sectional view for explaining an outflow portion used in the outflow method of the glass melting furnace.

FIG. 4 is a schematic cross-sectional view for explaining an outflow portion used in an outflow method of a glass melting furnace in a second embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection / dissolution / refining tank 2 Homogeneous / outflow tank 3 Connection pipe 4,5 Outflow pipe 4a, b, 5a, b Electrode terminal member 6 Heat resistant / insulation member 7 Furnace wall iron plate 8 Stirring prop 9 Heater 10 Input unit 11 Support member DESCRIPTION OF SYMBOLS 12 Fixed support stand 13 Glass raw material 14 Molten glass 15a, 15b, 22 Melt outflow glass 16, 21 Receiving mold 17, 18 Fixed support member 19, 20 Outflow pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Isamu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masayuki Tomita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the corporation

Claims (3)

[Claims] 1. A melting furnace for discharging a predetermined amount of molten glass flow from an outflow pipe of a melting crucible of optical glass, wherein the outflow pipe is provided below an outlet of a first outflow pipe connected to the melting crucible. A glass outflow device comprising a second glass outflow pipe separated from the melting crucible. 2. The method according to claim 1, wherein the position of the outlet of the second glass outflow pipe is controlled relative to the position of the outlet of the first outflow pipe connected to the melting crucible. The glass outflow device according to claim 1. 3. The first outflow pipe and the second glass outflow pipe connected to the melting crucible are made of platinum or a platinum alloy, and each of the first outflow pipe and the second outflow pipe has a flow rate of the molten glass which is individually controlled by direct current heating. The glass outflow device according to claim 1, wherein the glass outflow device is configured to control the flow rate.