Skull pot for the melting or refining of inorganic substances, especially glasses and glass ceramics

专利摘要:
The present invention relates to a skull crucible (1) for melting, crystallizing or refining an inorganic material. The crucible comprises a crucible wall (1.1), a crucible bottom (1.2), and an induction coil (2) surrounding the crucible wall (1.1) to couple high frequency energy to the crucible contents. The crucible wall 1.1 is formed of a ring of metal pipe that can be connected to a cooling medium. Slits are formed between adjacent metal pipes. A bottom 1.2 is provided for the discharge of the melt 3. A sleeve 4 is installed for the discharge. The inlet end (4.1) of the sleeve (4) is projected in such a way to the inner chamber of the skull crucible (1), during use, so that the melt is (3) controlled through the crystallized bottom layer (3.3) without compromising quality. Can be removed with
公开号:KR20020038727A
申请号:KR1020027001999
申请日:2000-08-16
公开日:2002-05-23
发明作者:힐데가르트 뢰머；우베 콜베르그；구이도 레케
申请人:게르하르트 암라인, 루드비히 비르스；카알-차이스-스티프퉁 트레이딩 에즈 쇼옷트 그라스；
IPC主号:

专利说明:

Skull pot for the melting or refining of inorganic substances, especially glasses and glass ceramics}
[2] Such crucibles have crucible walls. It is generally cylindrical. It consists of a vertical metal tube ring. There is a slot between adjacent tubes. The crucible bottom may also consist of a metal tube. It may also be composed of a refractory material. At its end is attached a vertical pipe for coolant supply or discharge.
[3] Heating takes place through an induction coil surrounding the crucible wall and coupling high frequency energy to the crucible contents.
[4] Skull crucibles for the melting of inorganic materials are known, for example, from EP 0,528,025 Bl.
[5] The skull crucible is operated as follows. The crucible is filled with broken glass pieces or mixtures thereof. The glass or melt is first preheated to achieve minimal conductivity. Preheating is usually done by burner heating. Once the coupling temperature is obtained, more energy can be supplied by high frequency energy radiation. Also during such an operation, the melt can be further heated by high frequency energy through a burner or through a hot exhaust gas which can affect the upper melt.
[6] Upon cooling, a solidified melt layer is formed on the outer surface of the metal tube constituting the crucible wall. Preference is given to a layer of crystalline material. This is desirable for thermal insulation as compared to the glassy layer. This outer layer protects the crucible wall from aggressive or hot-melt corrosion. This cooled outer layer is either glassy or crystalline depending on the glass melt.
[7] The floor is also cold because the floor is cooled like the wall. Likewise a glassy or crystalline cold bottom layer is formed. This is undesirable for filling the melt through the bottom drain. To transfer the melt by drainage, the hard bottom layer must be broken or re-melted using an additional heating system. The effect of producing such a crystal layer on the passage of the melt fluid is nucleating agent, which is undesirable. Also, because the coil ends 2-5 cm above the floor, the HF region becomes weaker.
[8] High frequency energy can only be usefully used to heat the inside of the skull crucible. However, it cannot be used to specifically heat the cooled bottom region. In addition, even if the layer close to the bottom is heated using induction heating, the heat is dissipated by the bottom cooling. This leads to a decay of the energy input compared to the uncooled central zone.
[9] Improving the performance of both high frequencies together raises the temperature of the bottom to solve the problem. However, the extra area of the skull crucible becomes overheated. This can lead to evaporation accompanied by waves.
[10] There is very little literature on special techniques for discharging glass melts from skull crucibles. The only technology is the outlet. U. S. Patent No. 5,567, 218 describes a relatively large outlet with little cooling. It is equipped with a slide that cools well. At the same time a short ceramic sleeve protrudes into the melt. It has the function of thermally blocking the discharge zone to facilitate the discharge. This document also publishes various variants with discharge devices that are indirectly heated.
[11] These embodiments have little or no sensitivity to crystallization suitable for such melting, which results in the disadvantage that the melt has various crystals and waves after discharge. In the melt without optical-crystallization-sensitivity, crystals are formed by such emissions in the ceramic case described above.
[12] This will interfere with the removal of the melt from the bottom. Emission control is not possible, and in particular, it is impossible to control the discharge speed. In addition, there is a risk that the ceramic sleeve will melt again quickly and cause blemishes on the glass.
[1] The present invention relates to a so-called skull crucible for melting or refining inorganic materials, in particular glass and glass ceramics.
[26] 1 is a cross-sectional view of an example of a skull crucible according to the present invention.
[27] 2 is a cross-sectional view of another example of a skull crucible according to the present invention.
[13] It is an object of the present invention to provide a skull crucible capable of controlling and discharging the melt at the bottom so as to be able to produce glass of high quality, in particular without compromising glass quality.
[14] This object is solved by claim 1 of the present invention. The inventors have recognized the possibility that the problem of removal will be solved if the melt is removed in the hotter zone. Thus, according to the invention, the cold, crystallized glass at the bottom is not removed.
[15] Therefore, the crystalline material does not reach the ingot from the bottom, and the melt does not pass through the crystallized bottom layer during the casting process, so that no new nucleus is formed and no modified product, which is heavier than glass, is produced. Will remain. In addition, the sleeve can have a length and diameter corresponding to the viscosity of the melt so that the discharge of the melt can be done without causing a wave in the mold. Thus, this technique can be used to produce optical glass free of crystals and defects.
[16] Another advantage of the present invention is as follows. The sleeve height is adjusted to allow continuous melting without stopping the flow of glass. Residual gas remaining in the crucible further enables HF coupling.
[17] Thus, the process can continue immediately. At the same time, a fresh non-uniform mixture can be replenished without heating, for example by a regeneration process with burner flames.
[18] This is particularly desirable for glasses with volatile batch components that are strongly evaporated or atomized when burner heating is carried out, as well as glasses with minimal conductivity that are difficult to conduct.
[19] Two platinum crucibles were used as an embodiment. Common to both is that the discharge pipe and sleeve are constructed of platinum or platinum alloy and the discharge pipe is suitable for 50 Hz resistive heating devices. Platinum is used because it is stable under oxidation conditions up to 1600 ° C and does not leave any signs of discoloration on the glass. For higher temperatures, sleeves made of iridium, molybdenum, wolfram or mixtures thereof are used.
[20] In a first embodiment, if the coupling is done simultaneously during or after casting, the discharge pipe height is ideally one third of the total melt height. If the molten material is contaminated by the material of the platinum sleeve, the sleeve is preferably shorter. In this case 2-6 cm long sleeves are suitable. The glass sealing between the platinum flange and the water cooled skull crucible is ensured by the quartz plate as well as the air cooling of the ring around the platinum flange. Depending on the melting and corrosion requirements, the quartz porcelain plate is 1 to 2 cm thick. In all cases, the platinum sleeve must protrude at least 1 cm above the quartz porcelain plate.
[21] In the second embodiment, the structure is optimized to meet the requirement of not including platinum. In this embodiment, platinum is separated from the melt by the solid glass layer during melting and no dissolution occurs. Immediately before casting, cooling is reduced and completely eliminated so that the glass on the platinum vessel is heated above the change threshold temperature. When all the crystals in the exhaust melt, the 50 Hz resistive heating of the platinum pipe is raised to the casting temperature and the melt is removed. When the glass limit layer melts, the temperature can be measured using a thermoelectric element attached to the sleeve.
[22] The thermoelectric element is removed from the cooled sleeve through the gas outlet and transferred through the capacitor to the measuring device. The capacitor helps to filter and mitigate possible HF interference signals.
[23] The platinum discharge sleeve is in principle in contact with the skull crucible, which is water cooled from the electrical layer. However, this embodiment is not preferred because the platinum outlet sleeve may be affected by the water cooling of the skull crucible and be overcooled. This embodiment may be desirable for very aggressive glass melting, since the glass sealing problem between the skull crucible and the platinum sleeve does not apply.
[24] Where glass sealing is not a problem, it is always desirable that no electrical coupling of the flange and metallic skull crucible occurs. This leads to lower HF interference levels in platinum heating. If the electrical coupling between the flange and the metallic skull crucible does not occur, the distance between the two parts must be at least 0.5 cm, with the gap between them filled with insulating ceramic. The most preferred material is quartz ware.
[25] Another example of a discharge device is a quartz glass pipe that is heated directly below the bottom of the crucible and protrudes several centimeters into the melt in the upper section. The advantage of this embodiment is that the melt contains no platinum. The disadvantage is that the emission stability is limited due to corrosion by aggressive glass melting.
[28] Lanthanan crown series glass was melted and cast. The HF energy was supplied using a generator with a 1 MHz frequency. The volume of the melt was 8 liters. The height of the melt of the skull crucible was 21 cm. The HF energy required for casting is 30 KW. The upper decay temperature of the glass is 1040 ° C. Casting temperature is 1100 degreeC. The temperature in the crucible differs from 1,000 ° C. at the bottom, 1150 ° C. at the center and 1100 ° C. at the surface. This means that the crystal layer is at the bottom during casting since the sleeve structure does not have an adverse effect.
[29] A 50 cm long, 8 mm diameter platinum pipe and a 10 mm diameter and 7 cm length sleeve were used. The platinum tube has a flange installed at the bottom of the crucible. It is set directly on the aluminosilicate bottom plate of the skull crucible and a thermal circuit is attached. The distance between the flange and the skull crucible is 5 cm. The upper edge of the flange is air cooled. At very corrosive glass melts or at high refining temperatures, air cooling can be converted to water cooling if necessary. At the bottom of the platinum pipe is another current supply plate lug for flange heating. The platinum flange is heated up to 1400 ° C by the heating circuit between the flange and the plate lug. Only the pipe itself is heated, while the glass protruding sleeve is only heated indirectly from the platinum tube and the hot-melt.
[30] The platinum discharge pipe is not heated during melting and refining. About 1 to 2 hours before casting, the crucible is set to casting temperature and the platinum flange also slowly reaches the casting temperature. When both reach the desired temperature, the melt and the exit glass heat up.
[31] If an air cooled sleeve is used, the air cooling of the sleeve is also turned off to match the temperature in the melt for the pipe and the casting.
[32] The flow of glass is stopped by the stopper until the desired temperature is reached and the sleeve is at least 1050 ° C. and certainly above the limiting temperature limit.
[33] The present invention will be described in more detail with reference to the drawings.
[34] 1 is a cross-sectional view of an example of a skull crucible according to the present invention.
[35] 2 is a cross-sectional view of another example of a skull crucible according to the present invention.
[36] The skull crucible shown in the figures is used for melting and refining of inorganic materials, in particular glass or glass ceramics, especially broken glass or so-called non-uniform glass mixtures.
[37] The skull crucible has walls 1 and 1. It consists of a ring of vertical metal pipes connected to each other and to which a refrigerant such as water is attached.
[38] The crucible bottoms 1 and 2 of the skull crucible consist of quartz porcelain plates, which are also cooled by the air from the pipes 1 and 3.
[39] Walls 1 and 1 are surrounded by induction coil 2. This is a high frequency device that supplies high frequency energy to the contents of the skull crucible.
[40] As shown, melt 3 is inside the skull crucible. The walls 1, 1 and bottom 1,2 of the skull crucible are covered with crystallized layers 3, 1 and 3, 2, respectively. The products 3,3 shown at the bottom can be produced in several glass forms and settle from the inside of the melt to the bottom.
[41] According to the invention, a platinum sleeve 4 is provided for the discharge. The upper end 4,1 of the sleeve 4 protrudes firmly into the upper part of the bottom 1,2. It is clear that the upper end is located in an area far from the crystallized bottom layer so that the temperature here is above the change temperature. Due to the position of the upper end 4,1 there is no risk that the product 3,3 will enter the sleeve 4 and impair the quality of the glass melt removed.
[42] The skull crucible 1 of FIG. 2 basically has the same structure as the skull crucible of FIG. It also has a sleeve 4 for removing the glass melt. The upper end 4,1 of the sleeve 4 is also located in the relatively hot area of the glass melt.
[43] However, the cooling system is anchored in the region of the sleeve 4 located inside the melt 3 as compared to FIG. The cooling system is mantle 4.2 covering the top of the sleeve 4. A pupil with inlet 4,3 and outlet 4,4 is formed between the mantle 4,2 and the upper region of the sleeve 4. Refrigerants, for example gas, are supplied to inlets 4 and 3. Thermoelectric elements 4 and 5 are mounted in the pupil.
[44] When the skull crucible is operated, it is effective to adjust the temperature of the sleeve protrusion to the melt 3 so that the temperature of the sleeve 4 is kept in a low molten state. At the same time, the temperature must be low enough to form a solid glass or crystal layer, and as the melt is discharged the temperature rises above the decay temperature.
[45] It is also effective to keep the bottom of the skull crucible at a lower temperature than the glass melt. This is preferable because there is less corrosion at the bottom.
[46] The present invention enables the production of high quality glass.

权利要求:
Claims (6)
[1" claim-type="Currently amended] A crucible wall (1.1) formed of a ring of metal tubes that can be connected with a coolant and having voids between adjacent tubes;
A crucible bottom 1.2 at which the melt is discharged;
An induction coil 2 enclosing the crucible wall 1.1 and capable of being coupled to the crucible contents by high frequency energy; And
A sleeve (4) installed for discharge, having an inlet end (4,1) projecting into the inner chamber of the skull crucible so that the melt is removed from the bottom layer crystallized in a controlled manner without loss of quality,
Skull crucibles for melting or refining inorganic materials, in particular glass or glass ceramics, comprising (1).
[2" claim-type="Currently amended] Skull crucible according to claim 1, characterized in that the height of the sleeve (4) is one tenth to one half of the melt height measured from the crucible bottom (1.2).
[3" claim-type="Currently amended] Skull crucible according to claim 1 or 2, characterized in that the sleeve (4) is provided with a temperature control device.
[4" claim-type="Currently amended] 4. A skull crucible according to claim 3, characterized in that the upper part of the sleeve (4) protruding from the melt to form a pupil has a double wall, the pupil having an inlet (4.3) and an outlet (4.4) for the refrigerant.
[5" claim-type="Currently amended] Skull crucible according to any one of the preceding claims, characterized in that the sleeve (4) is formed of two coaxial sleeves, the outer sleeve is a metal jacket and the inner sleeve is a quartz glass tube.
[6" claim-type="Currently amended] The skull crucible according to any one of claims 1 to 5, wherein the sleeve is height adjustable.

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同族专利:

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公开号 | 公开日

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AU7276500A|2001-03-19|

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DE19939781C2|2003-06-18|

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JP2003507314A|2003-02-25|

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US6889527B1|2005-05-10|

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DE19939781A1|2001-02-22|

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WO2001014268A1|2001-03-01|

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EP1206421A1|2002-05-22|

引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
1999-08-21|Priority to DE19939781A

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1999-08-21|Priority to DE19939781.3

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2000-08-16|Application filed by 게르하르트 암라인, 루드비히 비르스, 카알-차이스-스티프퉁 트레이딩 에즈 쇼옷트 그라스

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2000-08-16|Priority to PCT/EP2000/007987

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2002-05-23|Publication of KR20020038727A

优先权:

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申请号 | 申请日 | 专利标题

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DE19939781A|DE19939781C2|1999-08-21|1999-08-21|Skull crucible for melting or refining inorganic substances, especially glasses and glass ceramics|

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DE19939781.3|1999-08-21|

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PCT/EP2000/007987|WO2001014268A1|1999-08-21|2000-08-16|Skull pot for melting or refining inorganic substances, especially glasses and glass ceramics|