JP2024039288A - Residual thickness measuring device, residual thickness measuring method, and glass manufacturing method - Google Patents

Abstract

The present invention provides a technique for measuring the residual thickness of a wall of a melting tank without stopping electrical heating of molten glass. A residual thickness measuring device measures the residual thickness of a wall of a melting tank that stores molten glass that is heated by electricity. The remaining thickness measuring device includes a metal scale that is inserted into a through hole in the wall, and an insulating cover that covers at least a portion of the outer peripheral surface of the scale outside the wall. [Selection diagram] Figure 1

Description

The present disclosure relates to a residual thickness measuring device, a residual thickness measuring method, and a glass manufacturing method.

The melting tank stores molten glass obtained by melting glass raw materials. The walls of the melting tank are in contact with the molten glass and gradually erode over time. Therefore, the wall thickness gradually decreases. When the wall thickness falls below a threshold, life-extending repairs may be performed or the melter may be taken out of service at the end of its lifespan.

Patent Document 1 describes that the remaining thickness of the side wall of the dissolving tank is measured by inserting a metal scale into the joints between the bricks forming the side wall of the dissolving tank (Patent Document 1 (See paragraph [0006]).

Patent Documents 2, 3, and 4 disclose techniques for heating molten glass with electricity. The molten glass is electrically heated by a plurality of electrode rods inside the melting tank. Joule heat is generated by applying a voltage to the molten glass and causing a current to flow through the molten glass.

Japanese Patent Application Publication No. 2012-13512 JP2018-193268A Special Publication No. 61-21170 Japanese Patent Application Publication No. 4-342425

When using a metal scale to measure the remaining thickness of the wall of a melting tank for electrical heating, the electrical heating of the molten glass must be temporarily stopped to prevent electric shock to the worker when measuring the remaining thickness. I will do it.

If the electrical heating of the molten glass is temporarily stopped, the temperature of the molten glass will fluctuate, and the quality of the product glass may fluctuate. In particular, as wall erosion progresses and the remaining thickness decreases, the frequency of measuring the remaining thickness increases, which increases the risk of temporarily stopping electrical heating.

One aspect of the present disclosure provides a technique for measuring the residual thickness of the wall of a melting tank without stopping electrical heating of molten glass.

A residual thickness measuring device according to one aspect of the present disclosure measures the residual thickness of a wall of a melting tank that stores molten glass that is heated by electricity. The remaining thickness measuring device includes a metal scale that is inserted into a through hole in the wall, and an insulating cover that covers at least a portion of the outer peripheral surface of the scale outside the wall.

According to one aspect of the present disclosure, at least a portion of the outer circumferential surface of the scale is covered with an insulating cover, so electric shock to workers can be suppressed, and the wall of the melting tank can be prevented from being electrically heated without stopping the electrical heating of the molten glass. The remaining thickness can be measured.

FIG. 1 is a cross-sectional view showing a residual thickness measuring device according to an embodiment, in which (A) is a cross-sectional view showing a scale inserted into a through hole in a side wall, and (B) is a cross-sectional view showing a state where a cover is placed in contact with a side wall. It is a sectional view showing a state in which they are in contact with each other, and (C) is a sectional view showing a state in which the scale is extracted from a through hole in a side wall. FIG. 2 is a cross-sectional view showing a residual thickness measuring device and a dissolving tank according to a modified example, (A) is a cross-sectional view showing the state before the scale is inserted into the through hole in the side wall, and (B) is the scale FIG. 3C is a cross-sectional view showing the scale inserted into the through-hole of the side wall; FIG.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that in each drawing, the same or corresponding configurations are denoted by the same reference numerals, and the description thereof may be omitted. In the specification, "~" indicating a numerical range means that the numerical values written before and after it are included as lower and upper limits.

With reference to FIG. 1, a residual thickness measuring device 100 according to an embodiment will be described. The remaining thickness measuring device 100 measures the remaining thickness of the wall of the dissolution tank 10. The melting tank 10 stores molten glass G obtained by melting glass raw materials. The walls of the melting tank 10 are in contact with the molten glass G and are gradually eroded over time. Therefore, the thickness of the wall of the dissolution tank 10 gradually decreases. When the thickness of the wall of the dissolving tank 10 becomes smaller than a threshold value, repairs are performed to extend the life of the dissolving tank 10, or the operation of the dissolving tank 10 is stopped due to the end of its life.

The melting tank 10 has a side wall 11 that surrounds the molten glass G from the side, and a bottom wall 12 that supports the molten glass G from below. The side wall 11 and the bottom wall 12 are also collectively referred to simply as a wall. The wall of the melting tank 10 is composed of a plurality of bricks. The plurality of bricks are arranged with gaps so that they do not come into contact with each other due to thermal expansion. The gap is large enough to prevent the molten glass G from leaking, and is, for example, 0.1 mm to 5 mm. A gap between adjacent bricks can be used as a through hole 13 for measuring the remaining thickness. Since there are multiple gaps between adjacent bricks, it is possible to measure the remaining thickness at multiple locations.

The remaining thickness measuring device 100 is used, for example, to measure the remaining thickness of the side wall 11. Note that the remaining thickness measuring device 100 may be used to measure the remaining thickness of the bottom wall 12. The remaining thickness measuring device 100 includes a scale 110. The scale 110 is inserted into the through hole 13 of the side wall 11 and brought into contact with the molten glass G, as shown in FIG. 1(A). Since the molten glass G loses heat to the walls of the melting tank 10, it becomes hard to some extent near the walls and prevents scale 110 from entering.

The scale 110 is, for example, plate-shaped. The thickness of the plate-shaped scale 110 is large enough to allow the scale 110 to be inserted into a gap between adjacent bricks, and is, for example, 0.1 mm to 3 mm. Note that the scale 110 may be rod-shaped. The rod-shaped scale 110 has a diameter of, for example, 0.1 mm to 3 mm.

The scale 110 has a distal end surface 111 that contacts the molten glass G, a proximal end surface 112 facing opposite to the distal end surface 111, and an outer circumferential surface 113. Furthermore, the scale 110 has graduations 114 that indicate the distance from the tip surface 111. Scale 114 may indicate distance from proximal surface 112. In any case, as will be described in detail later, the remaining thickness of the side wall 11 can be measured using the scale 114 as shown in FIGS. 1(A) to 1(C).

When the scale 110 is inserted into or pulled out from the through hole 13 of the side wall 11, it rubs against the bricks forming the side wall 11. If the scale 110 is made of metal, the scale 110 is difficult to break and the work is easy. Therefore, in this embodiment, a metal scale 110 is used.

The molten glass G is electrically heated inside the melting tank 10 by a plurality of electrodes (not shown). By applying a voltage to the molten glass G and causing a current to flow through the molten glass G, Joule heat is generated. The electrode is, for example, rod-shaped. A rod-shaped electrode is inserted into the molten glass G from the bottom wall 12 of the melting tank 10. Note that a rod-shaped electrode may be inserted into the molten glass G from above or from the side.

When the plurality of electrodes energize and heat the molten glass G with the tip end surface 111 of the scale 110 in contact with the molten glass G, electricity flows to the metal scale 110 via the molten glass G. Note that a plurality of electrodes and a gas burner may be used together as a heater for heating the molten glass G. Also in this case, electricity flows through the molten glass G to the metal scale 110.

Therefore, the remaining thickness measuring device 100 includes an insulating cover 120 that covers at least a portion of the outer circumferential surface 113 of the scale 110 on the outside of the side wall 11. The operator holds the scale 110 through the cover 120. Therefore, electric shock to the worker can be suppressed, and the remaining thickness of the side wall 11 can be measured without stopping the electrical heating of the molten glass G. Temperature fluctuations in the molten glass G can be suppressed during residual thickness measurement, and fluctuations in the quality of the product glass can be suppressed. The insulation resistance of the cover 120 is preferably 0.4 MΩ or more, more preferably 100 MΩ or more, and still more preferably 1 GΩ or more. The insulation resistance of the cover 120 is preferably as large as possible, and is not particularly limited, but from the viewpoint of feasibility, it is preferably 100 TΩ or less.

The cover 120 only needs to be provided outside the side wall 11 and, unlike the scale 110, does not need to be inserted into the through hole 13 of the side wall 11. This is because the worker performs the work outside the side wall 11. Further, by not inserting the cover 120 into the through hole 13 of the side wall 11, it is possible to prevent the cover 120 from breaking inside the through hole 13, and it is possible to prevent pieces of the cover 120 from being left behind in the through hole 13.

The cover 120 has a covering portion 121 that covers at least a portion of the outer circumferential surface 113 of the scale 110. Preferably, the entire outer peripheral surface 113 of the scale 110 is covered with the covering portion 121 in a cross section perpendicular to the longitudinal direction (left-right direction in FIG. 1) of the scale 110. Although the cover 120 is slidable in the longitudinal direction of the scale 110 in this embodiment, it may be non-slidable.

When the scale 110 is plate-shaped, the covering portion 121 includes, for example, a pair of insulating plates 121a and 121b. A pair of insulating plates 121a and 121b are arranged with the plate-shaped scale 110 in between. The pair of insulating plates 121a and 121b can be obtained, for example, by processing bricks. The width of the pair of insulating plates 121a and 121b is preferably larger than the width of the scale 110. Contact between the scale 110 and the worker can be restricted.

The covering portion 121 may include an insulating tape (not shown) in addition to the pair of insulating plates 121a and 121b. The insulating tape is wound around a pair of insulating plates 121a and 121b. Thereby, the entire outer circumferential surface 113 of the scale 110 can be covered with the covering portion 121 in a cross section perpendicular to the longitudinal direction of the scale 110.

Note that when the scale 110 is rod-shaped, the covering portion 121 includes, for example, a hollow insulating cylinder. The hollow insulating cylinder can be obtained, for example, by processing bricks. A scale 110 is inserted into the hollow insulating cylinder. Thereby, the entire outer circumferential surface 113 of the scale 110 can be covered with the covering portion 121 in a cross section perpendicular to the longitudinal direction of the scale 110.

The remaining thickness measuring device 100 includes a restriction member 130 between the scale 110 and the cover 120 that restricts the transfer of heat from the scale 110 to the cover 120. Restriction member 130 has a lower thermal conductivity than both scale 110 and cover 120, for example. Thereby, the temperature rise of the cover 120 can be suppressed. Note that if the thermal conductivity of the cover 120 is sufficiently low, the limiting member 130 may be omitted.

Preferably, the entire outer peripheral surface 113 of the scale 110 is covered with the limiting member 130 in a cross section perpendicular to the longitudinal direction of the scale 110. The limiting member 130 is integrated with the cover 120 and is slidable together with the cover 120 in the longitudinal direction of the scale 110. Note that the limiting member 130 may be non-slidable.

The limiting member 130 is obtained, for example, by processing a brick. The bricks forming the limiting member 130 have lower thermal conductivity than the bricks forming the cover 120. On the other hand, it is preferable that the bricks forming the cover 120 have higher electrical resistivity than the bricks forming the limiting member 130.

The limiting member 130 may be a spacer that forms an air layer (not shown) between the scale 110 and the cover 120. The thermal conductivity of the air layer is lower than that of brick. Therefore, by forming the air layer, the transfer of heat from the scale 110 to the cover 120 can be further restricted.

Next, referring again to FIG. 1, an example of a method for measuring the remaining thickness will be described. For example, as shown in FIG. 1A, the operator inserts the scale 110 into the through hole 13 of the side wall 11, and with the tip surface 111 of the scale 110 in contact with the molten glass G, the The position is read on the graduations 114 of the scale 110. The remaining thickness T of the side wall 11 is equal to the distance L1 from the tip surface 111 of the scale 110 to the outer surface 15 of the side wall 11.

As shown in FIG. 1(B), the operator slides the cover 120 with respect to the scale 110 with the tip surface 111 of the scale 110 in contact with the molten glass G, and brings the cover 120 into contact with the side wall 11. You may let them. In this case, the operator measures the remaining thickness T of the side wall 11 by reading the distance L2 from the base end surface 112 of the scale 110 to the end surface 129 of the cover 120 on the opposite side to the side wall 11. The length of the scale 110 and the length of the cover 120 are measured in advance and referred to when measuring the remaining thickness T.

The operator may prevent the cover 120 from sliding with respect to the scale 110 in the state shown in FIG. 1(B), and then pull out the scale 110 from the through hole 13 of the side wall 11 as shown in FIG. 1(C). In this case, the operator measures the remaining thickness T of the side wall 11 by reading the distance L1 from the tip surface 111 of the scale 110 to the end surface 128 of the cover 120 facing the side wall 11.

Note that after the operator pulls out the scale 110 from the through hole 13 of the side wall 11 as shown in FIG. The remaining thickness T of the side wall 11 may be measured by reading the distance L2. The length of the scale 110 and the length of the cover 120 are measured in advance and referred to when measuring the remaining thickness T.

Next, with reference to FIG. 2, a residual thickness measuring device 100 according to a modification will be described. The differences will be mainly explained below. The remaining thickness measuring device 100 includes a metal scale 110, an insulating cover 120, and a limiting member 130. The cover 120 includes a covering portion 121 that covers at least a portion of the outer circumferential surface 113 of the scale 110, and a facing portion 122 that faces the proximal end surface 112 of the scale 110.

The covering portion 121 and the opposing portion 122 are integrated. Thereby, electric shock to the worker can be further suppressed. Note that when the covering portion 121 and the opposing portion 122 are integrated, the cover 120 may not be able to slide in the longitudinal direction of the scale 110. The cover 120 may include a lid portion 123 facing the side wall 11. The lid portion 123, the covering portion 121, and the opposing portion 122 may be integrated.

The remaining thickness measuring device 100 includes a cursor 140 that contacts the side wall 11 from the outside and slides relative to the scale 110. Cursor 140 is slidable in the longitudinal direction of scale 110 and indicates the current position of cursor 140 with respect to scale 110. With the tip end surface 111 of the scale 110 in contact with the molten glass G and the cursor 140 in contact with the outer surface 15 of the side wall 11, the cursor 140 indicates the remaining thickness T of the side wall 11 on the scale 114. Providing the cursor 140 makes it easy to read the remaining thickness T.

Next, referring again to FIG. 2, an example of a method for measuring the remaining thickness will be described. The operator inserts the scale 110 into the through hole 13 of the side wall 11, and brings the tip surface 111 of the scale 110 into contact with the molten glass G, as shown in FIGS. 2(A) and 2(B), for example. Before the tip surface 111 of the scale 110 comes into contact with the molten glass G, the cursor 140 comes into contact with the outer surface 15 of the side wall 11, and the cursor 140 slides relative to the scale 110.

The operator measures the remaining thickness T of the side wall 11 by reading the distance L1 from the tip surface 111 of the scale 110 to the outer surface 15 of the side wall 11, as shown in FIG. 2(B). Cursor 140 is preferably transparent. However, even if the cursor 140 is opaque, it is sufficient that the cursor 140 has a shape that allows the operator to read the scale 114. For example, the cursor 140 may have a window for reading the scale 114. good.

The operator may prevent the cover 120 from sliding with respect to the scale 110 in the state shown in FIG. 2(B), and then pull out the scale 110 from the through hole 13 of the side wall 11 as shown in FIG. 2(C). In this case, the operator extracts the scale 110 from the through hole 13 of the side wall 11 as shown in FIG. Measure the remaining thickness T of No. 11.

Although the residual thickness measuring device, residual thickness measuring method, and glass manufacturing method according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

10 Dissolution tank 11 Side wall 12 Bottom wall 13 Through hole 100 Residual thickness measuring device 110 Scale 113 Outer surface 120 Cover

Claims (7)

A residual thickness measuring device for measuring the residual thickness of a wall of a melting tank that stores molten glass heated by electricity,
a metal scale inserted into the through hole in the wall;
an insulating cover that covers at least a portion of the outer peripheral surface of the scale on the outside of the wall;
A residual thickness measuring device comprising: The residual thickness measuring device according to claim 1, wherein the scale is plate-shaped or rod-shaped. The residual thickness measuring device according to claim 1 or 2, further comprising a restriction member between the scale and the cover that restricts transfer of heat from the scale to the cover. The remaining thickness measuring device according to claim 1 or 2, further comprising a cursor that abuts the wall from the outside and slides relative to the scale. The scale has a distal end surface that comes into contact with the molten glass, a proximal end surface that is opposite to the distal end surface, and the outer circumferential surface,
The cover has a covering portion that covers at least a portion of the outer circumferential surface of the scale, and a facing portion that faces the proximal end surface of the scale,
The remaining thickness measuring device according to claim 1 or 2, wherein the covering portion and the opposing portion are integrated. A residual thickness measuring method comprising measuring the residual thickness using the residual thickness measuring device according to claim 1 or 2. A glass manufacturing method comprising measuring the residual thickness using the residual thickness measuring device according to claim 1 or 2,
A glass manufacturing method comprising heating the molten glass with electricity.

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