JP7172221B2 - Method for adjusting temperature of heating element and method for manufacturing glass article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for adjusting the temperature of a heating element and a method for manufacturing a glass article.

Patent Document 1 discloses a heating element containing molybdenum disilicide as a main component as a heating element for heating molten glass. When this type of heating element is maintained in a low temperature range of 400° C. to 600° C. for a long time, silicon and molybdenum are simultaneously oxidized. Then, a phenomenon called "pesting" occurs in which a porous layer composed of silicon oxide and molybdenum oxide is formed on the surface of the heating element.

JP 2016-115620 A

When pesting occurs in the rod-shaped heating element, the outer diameter may increase due to expansion of the pesting portion. Therefore, when there are support portions that support the heat generating element so as to sandwich the heat generating element, if pestification occurs in the portion supported by the support portions of the heat generating element, there is a risk that a load will act on the support portion. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for adjusting the temperature of a heating element and a method for manufacturing a glass article, which can suppress the application of a load to a supporting portion that supports the heating element due to pesting of the heating element.

Means for solving the above problems and their effects will be described below.
A method for adjusting the temperature of a heating element that solves the above problems includes molybdenum disilicide having a heating portion that generates heat when energized, a terminal portion to which an electrode is attached, and an intermediate portion that connects the heating portion and the terminal portion. temperature of the heat generating element in a heating device comprising: In the adjustment method, when the portion of the intermediate portion supported by the support portion is assumed to be a first intermediate portion, the amount of heat released from the first intermediate portion via the support portion is changed to adjust the first intermediate portion. 1 Adjust the temperature of the middle part.

In the above heating device, the temperature of the intermediate portion of the heating element decreases as the amount of heat released to the outside through the support portion increases. Therefore, in the above-described temperature adjustment method, the temperature of the first intermediate portion of the heating element is adjusted by changing the amount of heat released from the supporting portion so that the temperature of the first intermediate portion of the heating element does not fall within the temperature range in which pestification occurs. adjust. Thus, the temperature adjustment method described above can suppress the load acting on the support portion due to the expansion of the first intermediate portion caused by the pestification.

In the method for adjusting the temperature of the heating element, it is preferable that the temperature of the first intermediate portion is adjusted by changing the amount of heat insulating material arranged around the support portion.
In the temperature control method described above, the amount of heat insulating material arranged around the support is changed to change the amount of heat released to the outside through the support. That is, the temperature adjustment method described above is a simple method, and the temperature of the first intermediate portion can be adjusted.

In the method for adjusting the temperature of the heating element, it is preferable that the temperature of the first intermediate portion is adjusted by adjusting the amount of electric power supplied to the heating element.
Since the heat generating element is also a heat conductor, the temperature of the intermediate portion connected to the heat generating portion changes according to the change in the amount of heat generated in the heat generating portion. Therefore, in the above-described temperature adjustment method, the amount of heat applied to the first intermediate portion is changed by adjusting the amount of power supplied to the heating element so that the temperature of the first intermediate portion does not fall within the temperature range where pesto formation occurs. do. Thus, the temperature adjustment method described above can suppress the load acting on the support portion due to the expansion of the first intermediate portion caused by the pestification.

In the method for adjusting the temperature of the heating element, when a portion of the intermediate portion between the first intermediate portion and the terminal portion is defined as a second intermediate portion, the temperature of the first intermediate portion is determined based on the temperature of the second intermediate portion. It is preferable to adjust the temperature of the part.

In the heat generating element, the temperature of the heat generating portion tends to be the highest, and the temperature of the terminal portion tends to be the lowest. Therefore, when the temperature of the second intermediate portion is higher than the pesting temperature, the temperature of the first intermediate portion, which is closer to the heat-generating portion than the second intermediate portion, tends to be higher than the pesting temperature of the second intermediate portion. Therefore, in the temperature adjusting method having the configuration described above, the temperature of the first intermediate portion is adjusted based on the temperature of the second intermediate portion, which is not supported by the supporting portion and whose temperature can be easily measured. Therefore, the temperature adjustment method can appropriately adjust the temperature of the first intermediate portion without measuring the temperature of the first intermediate portion, which is difficult to measure because it is supported by the supporting portion.

A method for manufacturing a glass article that solves the above problems includes a temperature adjustment step of adjusting the temperature of the heating element and a heating step of heating the glass in the heating chamber by the temperature adjustment method of the heating element described above.

According to the above configuration, in the method for manufacturing a glass article, it is possible to obtain the same effects as those of the method for adjusting the temperature of the heating element described above.

According to the above configuration, it is possible to suppress the application of a load to the support portion that supports the heat generating element due to the heat generating element becoming a pesto.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic of the manufacturing apparatus of the glass article which concerns on one Embodiment. FIG. 2 is a partial cross-sectional view of a heating device included in the manufacturing apparatus;

An embodiment of a glass article manufacturing apparatus and a glass article manufacturing method provided with a heating device will be described below.
As shown in FIG. 1, a glass article manufacturing apparatus 10 (hereinafter also referred to as "manufacturing apparatus 10") includes a supply device 11 that supplies frit, a heating device 12 that heats frit, and molten glass. a forming device 13 for forming into a glass article.

The supply device 11 supplies the raw material for glass to the heating device 12 . Glass raw materials are, for example, mixtures of silica sand, lime and soda ash.
The heating device 12 includes a melting furnace 20 as an example of a “heating chamber” that melts frit into molten glass MG, and a heating unit 30 that heats a furnace interior 21 of the melting furnace 20 .

As shown in FIG. 1, the melting furnace 20 has a bottom wall 22, side walls 23 and top wall 24 made of a refractory material such as brick. The side wall 23 is formed with an inlet 25 for frit and an outlet 26 for molten glass MG. As shown in FIG. 2 , the upper wall 24 is formed with a recess 27 that is recessed toward the furnace interior 21 and a connection hole 28 that connects the recess 27 and the furnace interior 21 of the melting furnace 20 . The recessed portion 27 and the connection hole 28 are spaces for arranging a heating element 40 of the heating unit 30 (to be described later) toward the furnace interior 21 . In this embodiment, the recesses 27 and the connection holes 28 are formed according to the number of the heating elements 40 of the heating unit 30 . In the cross-sectional view shown in FIG. 2 , the width of the recess 27 is larger than the width of the connection hole 28 .

As shown in FIG. 2 , the heating unit 30 has a heating element 40 that generates heat when energized, a support section 50 that supports the heating element 40 , and a heat insulating material 61 that surrounds the support section 50 . Further, as shown in FIG. 1, the heating unit 30 includes a power source 62 that supplies electric power to the heating element 40, an electric wire 63 that connects the heating element 40 and the power source 62, and a temperature measuring unit that detects the temperature of the heating element 40. 64 and .

The heating element 40 is a resistive heating element containing molybdenum disilicide as a main component and generating heat when energized. As an example, the heating element 40 comprises 70% by weight or more of molybdenum disilicide and less than 30% by weight of glass or ceramics. The heating element 40 of this embodiment is formed in a substantially U shape, but it may be formed in a wave shape or in a bar shape. Further, the heating element 40 has a substantially circular cross-sectional shape perpendicular to the longitudinal direction.

As shown in FIG. 2, the heating element 40 includes a heating portion 41 that generates heat when energized, a terminal portion 42 to which the electrode 631 of the electric wire 63 is attached, and an intermediate portion 43 that connects the heating portion 41 and the terminal portion 42. have. The heat generating portion 41 has a cross-sectional area smaller than that of the terminal portion 42 and the intermediate portion 43 so that the resistance value is higher than that of the terminal portion 42 and the intermediate portion 43 . Therefore, when the heating element 40 is energized, the heating portion 41 selectively generates heat. The terminal portions 42 are both end portions of the U-shaped heating element 40 . For example, an aluminum layer is preferably formed on the surface of the terminal portion 42 in order to make good electrical contact with the electrode 631 . The intermediate portion 43 connects the first intermediate portion 431 supported by the support portion 50, the second intermediate portion 432 connecting the first intermediate portion 431 and the terminal portion 42, and the first intermediate portion 431 and the heat generating portion 41. and a third intermediate portion 433 . The heat generating element 40 is supported by the supporting portion 50 so that the heat generating portion 41 is positioned inside the furnace 21 and the terminal portion 42 protrudes from the upper wall 24 .

The support portion 50 is made of a refractory such as brick. The support portion 50 has a first support portion 51 having a substantially rectangular parallelepiped shape and a second support portion 52 having a flat plate shape.
In the cross-sectional view shown in FIG. 2, the width of the first support portion 51 is narrower than the width of the recess 27 and wider than the width of the connection hole 28 . Two through holes 511 are formed in the first support portion 51 in the longitudinal direction. The inner diameter of the through hole 511 is larger than the outer diameter of the intermediate portion 43 of the heating element 40 . The terminal portion 42 and the intermediate portion 43 of the heating element 40 are inserted through the through hole 511 of the first support portion 51 .

The second support portions 52 are arranged according to the number of through holes 511 of the first support portion 51 . In the cross-sectional view shown in FIG. 2 , the width of the second support portion 52 is larger than the inner diameter of the through hole 511 of the first support portion 51 . The second support portion 52 is fixed to the upper end of the first intermediate portion 431 of the heating element 40 by a fixture such as a clamp, for example. That is, the second support portion 52 is fixed to the first intermediate portion 431 of the heating element 40 by radially tightening the first intermediate portion 431 .

As shown in FIG. 2, when the second support portion 52 is fixed to the first intermediate portion 431 of the heating element 40 inserted through the through hole 511 of the first supporting portion 51, the terminal portion 42 of the heating element 40 faces vertically upward. When the first support portion 51 is arranged as above, the second support portion 52 contacts the upper surface of the first support portion 51 . In this way, the supporting portion 50 supports the heating element 40 so as to surround the intermediate portion 43 (first intermediate portion 431) of the heating element 40. As shown in FIG.

The support portion 50 is arranged in the recess 27 of the melting furnace 20 . When the support portion 50 is arranged in the recess 27 , the heat generating portion 41 of the heat generating element 40 extends toward the furnace interior 21 through the connection hole 28 .

The heat insulating material 61 is, for example, an inorganic fiber such as glass wool, and is configured to suppress heat transfer from the melting furnace 20 to the outside. The heat insulating material 61 is arranged in the concave portion 27 of the upper wall 24 of the melting furnace 20 so as to surround the support portion 50 . The shape of the heat insulating material 61 may be block-like, sheet-like, or cotton-like.

The power source 62 may uniformly supply electric power to the plurality of heating elements 40 , or may individually change the electric power to be supplied to the plurality of heating elements 40 . The amount of heat generated by the heating element 40 changes depending on the amount of power supplied from the power source 62 . That is, the temperature in the furnace interior 21 of the melting furnace 20 changes.

The temperature measuring section 64 measures the temperature of the second intermediate portion 432 of the heating element 40 . The temperature measurement unit 64 may be a contact thermometer or a non-contact thermometer.
For the molding device 13, a molding method is selected according to the type of glass article. Examples of the method for molding the glass article include a roll-out method, an up-draw method, a float method and a down-draw method. The glass article molded by the molding device 13 is, for example, sheet glass, glass fiber, tube glass, or the like.

The operation of this embodiment will be described.
In the following description, the temperature of 400 to 600 degrees Celsius at which pesting progresses in molybdenum disilicide is also referred to as "NG temperature".

When the melting furnace 20 is used, electric power is supplied to the heating element 40 so that the temperature of the heating portion 41 of the heating element 40 is 1000 degrees or higher. On the other hand, since the heating element 40 has the heating part 41 arranged inside the furnace 21 and the terminal part 42 outside the furnace, the temperature gradually decreases from the heating part 41 toward the terminal part 42 . Therefore, if the temperature of the second intermediate portion 432 of the heating element 40 is lower than, for example, "NG temperature -50 degrees", the temperature of the first intermediate portion 431 is highly likely to be the NG temperature. In this case, if the temperature of the first intermediate portion 431 is maintained at the NG temperature, the first intermediate portion 431 expands as the first intermediate portion 431 becomes pestified, and a load may be applied to the support portion 50. .

Therefore, in the method of adjusting the temperature of the heat generating element 40, as shown by the two-dot chain line in FIG. Increase quantity. Then, the amount of heat radiation from the first intermediate portion 431 via the support portion 50 is reduced, and the temperature of the first intermediate portion 431 is increased. In the temperature adjustment method, the amount of the heat insulating material 61 is increased until the temperature of the second intermediate portion 432 becomes "NG temperature -50 degrees" or higher. This is because if the temperature of the second intermediate portion 432 becomes "NG temperature -50 degrees" or higher, the temperature of the first intermediate portion 431 closer to the heat generating portion 41 than the second intermediate portion 432 becomes higher than the NG temperature. is. Note that the temperature (=“NG temperature−50 degrees”) subject to the above determination is an example, and the temperature difference between the first intermediate portion 431 and the second intermediate portion 432 of the heating element 40 when energized is preferably set to

Moreover, since the heat generating body 40 is a heat conductor, the heat generated in the heat generating portion 41 is transferred toward the terminal portion 42 by thermal conduction. Therefore, the method for adjusting the temperature of the heating element 40 increases the amount of electric power supplied to the heating element 40 when the temperature of the second intermediate portion 432 is less than the "NG temperature -50 degrees." Then, the amount of heat absorbed by the first intermediate portion 431 increases because the amount of heat generated by the heat generating portion 41 increases. As a result, the temperature of the first intermediate portion 431 increases.

Thus, in the present embodiment, when the temperature of the second intermediate portion 432 is less than the “NG temperature −50 degrees”, the heat radiation amount of the first intermediate portion 431 of the heating element 40 is reduced, or the first intermediate portion 431 of the heating element 40 By increasing the heat absorption amount of the portion 431, the temperature of the first intermediate portion 431 is set higher than the NG temperature. As a result, the plague of the first intermediate portion 431 is suppressed, and the application of a load to the support portion 50 that supports the first intermediate portion 431 is suppressed.

The adjustment of the amount of the heat insulating material 61 and the adjustment of the electric power supplied to the heating element 40 may be performed manually or may be automated by a controller.
On the other hand, when the temperature of the heating element 40 becomes excessively high, the temperature adjustment method is to decrease the heat insulating material 61 or increase the temperature of the heating element 40 within a range in which the temperature of the first intermediate portion 431 does not become an NG temperature. The amount of power supplied may be reduced.

Then, after the temperature adjustment step of adjusting the temperature of the heating element 40 described above, or in parallel with the temperature adjustment step, a melting step (heating step) of melting the frit in the melting furnace 20 and forming the molten glass MG. A molding process is performed to produce a glass article.

Effects of the present embodiment will be described.
(1) The temperature adjustment method is to change the amount of heat radiation in the first intermediate portion 431 of the heating element 40 via the support portion 50 so that the temperature of the first intermediate portion 431 reaches the temperature at which pesto formation occurs (NG temperature). prevent it from happening. In this way, the above-described temperature adjustment method can suppress the load acting on the support portion 50 due to the expansion of the first intermediate portion 431 caused by the pestification.

(2) Specifically, the temperature adjustment method changes the amount of heat-insulating material 61 disposed around the support portion 50, thereby changing the amount of heat released from the first intermediate portion 431 of the heating element 40 via the support portion 50. Let In other words, the temperature adjustment method described above can adjust the temperature of the first intermediate portion 431 of the heating element 40 by a simple method.

(3) The temperature adjustment method changes the amount of heat applied to the first intermediate portion 431 by adjusting the amount of electric power supplied to the heating element 40, and the temperature of the first intermediate portion 431 increases to the temperature at which pesto formation occurs (NG temperature). In this way, the temperature adjustment method can suppress the load acting on the support portion 50 due to the expansion of the first intermediate portion 431 caused by the pestification.

(4) The temperature adjustment method adjusts the temperature of the first intermediate portion 431 based on the temperature of the second intermediate portion 432 whose temperature is easy to measure because it is not surrounded by the support portion 50 . Therefore, the temperature adjustment method can appropriately adjust the temperature of the first intermediate portion 431 without measuring the temperature of the first intermediate portion 431 which is difficult to measure because it is surrounded by the support portion 50 .

This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
The temperature adjustment method can adjust the temperature of the first intermediate portion 431 of the heating element 40 without changing the amount of the heat insulating material 61, for example, by replacing the heat insulating material 61 in use with a heat insulating material 61 having a different heat insulation performance. may be adjusted. In addition, when a plurality of block-shaped heat insulating materials 61 are arranged around the first intermediate portion 431, the temperature adjusting method is such that the first intermediate portion 431 is adjusted by changing the size of the gaps between the plurality of heat insulating materials 61. temperature may be adjusted.

If the heating device 12 is equipped with a temperature measuring part that can directly measure the temperature of the first intermediate part 431 of the heating element 40 , the temperature adjustment method is based on the temperature of the first intermediate part 431 . may be adjusted.

- The temperature measurement unit 64 may measure a portion having a temperature corresponding to the temperature of the first intermediate portion 431 . In this case, the temperature adjustment method may adjust the temperature of the first intermediate portion 431 based on the temperature of the corresponding portion.

- When the heating device 12 includes a plurality of heat generating elements 40, increasing the amount of heat generated by all the heat generating elements 40 may increase the temperature inside the furnace 21 more than necessary. Therefore, the temperature adjustment method may increase the amount of heat generated by one of the plurality of heat generating elements 40 while decreasing the amount of heat generated by the other heat generating elements 40 . According to this, the temperature of the first intermediate portion 431 of the one heating element 40 whose heat generation amount is increased can be set to the NG temperature or higher, and the temperature of the first intermediate portion 431 of the other heat generating element 40 whose heat generation amount is decreased can be increased to the NG temperature or higher. can be made below the NG temperature. In order to reduce the amount of heat generated by the other heating element 40, the amount of the heat insulating material 61 surrounding the support portion 50 of the other heating element 40 may be further reduced.

- In the heating device 12, the arrangement of the heating element 40 may be changed as appropriate. For example, the heating element may be arranged to penetrate the bottom wall 22 of the melting furnace 20 or may be arranged to penetrate the side wall 23 of the melting furnace 20 .

- The heating device 12 may heat articles other than glass. The heating device 12 may heat metals and ceramics, for example.
- The melting furnace 20 may be a heating chamber for keeping the temperature of the molten glass MG in addition to melting the frit into the molten glass MG. For example, the heating chamber may be a fining chamber, a throat, a feeder and a frit preheating chamber.

DESCRIPTION OF SYMBOLS 10... Manufacturing apparatus 11... Supply apparatus 12... Heating apparatus 13... Molding apparatus 20... Melting furnace (an example of a heating chamber) 21... Furnace interior 22... Bottom wall 23... Side wall 24... Top wall, 25... Inlet 26... Outlet 27... Recessed portion 28... Connection hole 30... Heating unit 40... Heat generating element 41... Heat generating part 42... Terminal part 43... Intermediate part 431... First intermediate part , 432... Second intermediate part 433... Third intermediate part 50... Support part 51... First support part 511... Through hole 52... Second support part 61... Heat insulating material 62... Power source 63... Electric wire 631...Electrode 64...Temperature measuring part.

Claims (5)

a heating element comprising molybdenum disilicide having a heating portion that generates heat when energized, a terminal portion to which an electrode is attached, and an intermediate portion that connects the heating portion and the terminal portion;
a support portion made of a refractory material that surrounds and supports the intermediate portion of the heating element;
a heat insulating material made of inorganic fibers and covering the periphery of the support;
A temperature adjustment method of the heating element in a heating device comprising a heating chamber in which the heating part of the heating element is arranged,
When the portion of the intermediate portion supported by the support portion is the first intermediate portion,
A temperature adjustment step of adjusting the temperature of the first intermediate portion by changing the amount of heat radiation from the first intermediate portion via the support portion,
The temperature adjusting step includes adjusting the temperature of the first intermediate portion by changing the amount of the heat insulating material.
A method for adjusting the temperature of a heating element, characterized by: The first intermediate portion of the heating element is arranged so as to penetrate a wall constituting the heating chamber,
2. The heating device according to claim 1, wherein the heat insulating material can be inserted between the wall and the support portion that supports the first intermediate portion from the outside of the heating chamber. body temperature regulation. 3. The method for adjusting the temperature of the heating element according to claim 1, wherein the temperature of the first intermediate portion is adjusted by adjusting the amount of power supplied to the heating element. When a portion of the intermediate portion between the first intermediate portion and the terminal portion is defined as a second intermediate portion,
The temperature adjustment method of the heating element according to any one of claims 1 to 3, wherein the temperature of the first intermediate section is adjusted based on the temperature of the second intermediate section. the temperature adjusting step of adjusting the temperature of the first intermediate portion of the heating element by the temperature adjusting method of the heating element according to any one of claims 1 to 4;
A method for manufacturing a glass article, comprising: a heating step of heating the glass in the heating chamber.

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