JPH04265228A - Vented tube for glass furnace feeder - Google Patents

Abstract

PURPOSE:To prevent crack initiation and to prolong life by providing a through- hole for heating the inside of a tube so that it may be elliptical and an angle of the major axis of the ellipse to the rotational direction of the tube may be the prescribed one. CONSTITUTION:A through-hole 6 in the shape of an ellipse consisting of a major axis 7 and a minor axis 8 is provided for a vented tube 5. When the tube 5 is turned about an axis of rotation 11 in a direction of rotation 9 and let the direction of rotation of the tube be 0, the through-hole is made so that the major axis ascends at 0 to 9O deg. angle to form a vented tube for glass furnace feeder.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vented tube for a glass oven feeder.

0002

2. Description of the Related Art In the glass manufacturing process for bottles and tableware, a vented tube is used in the feeder section of a glass melting furnace for stirring the glass.

The role of the feeder is to melt and clarify glass in a glass melting kiln in the form of a gob at a temperature suitable for molding.
It also means supplying a constant weight to a molding machine, etc.

FIG. 1 shows the general structure of a glass oven feeder section 1. Glass supplied from a kiln is often cooled, homogenized in a spout section 2, extruded from an orifice 3 by a plunger 4, and cut into gob shapes.

[0005] The vented tube 5 rotates to stir the glass. In order to minimize the temperature difference between the inside and outside of the tube, the vented tube 5 is provided with three to four perfect circular through holes in the circumferential direction of the side surface above the portion of the tube that contacts the glass. The upper side of the vented tube 5 is in contact with the atmosphere, and the lower side is in contact with hot glass. Therefore, in order to suppress the temperature difference between the inside and outside of the tube, hot air is blown into the through hole.

[0006]

[Problems to be Solved by the Invention] Conventional vented tubes having perfectly circular through holes are prone to cracks due to stress generated around the through holes during use, that is, during rotation, forcing the operation to stop. There is. This is believed to occur because the tube is subjected to resistance from the glass in a direction opposite to the direction of rotation. Twisting force acts on the tube,
It is thought that stress is concentrated around the through hole.

[0007]

[Means for Solving the Problem] The present invention provides a vented tube of a glass melting furnace feeder section, in which the through hole for internal heating of the tube is made oval, and when the rotation direction of the tube is set to 0°, the length of the through hole is oval. The long axis of the circle moves upwards from 0 to 9.
This is a vented tube for glass kiln feeders that is tilted at 0°.

In the present invention, stress analysis was performed using a computer in order to examine countermeasures. The analysis was performed on a three-dimensional model using general-purpose finite element analysis software. In the present invention, thermal conditions were not considered, and only mechanical stress was studied. It has been found that by limiting the hole shape, the stress generated around the through hole during rotation of the vented tube becomes extremely small, regardless of the hole diameter, hole position, and number of holes.

FIG. 2 is a diagram schematically illustrating the vented tube of the present invention.

As shown in FIG. 2, the vented tube 5
The shape of the through hole 6 is preferably oval. The ellipse has a major axis 7 and a minor axis 6. It is assumed that the vented tube 5 rotates in a rotation direction 9 around a rotation shaft 11. At this time, it is considered that resistance is generated by the glass 12 in a direction opposite to the rotational direction 9.

According to experiments, the direction of rotation 9 of the tube was set to 0.
The possible range of the upward inclination 10 of the long axis is 1° to 89°, and the preferable range is 30° to 60°. Further, the ratio of the long axis 7 to the short axis 8 is preferably in the range of 1.5:1 to 3:
It is 1. At least within these ranges, a stress relieving effect on the vented tube can be observed.

0012

[Operation] The stress around the through hole becomes extremely small, so
Cracks are less likely to form in the tube.

[0013]

[Example] By changing the shape of the tube, changes in stress generated around the through hole on the side surface of the tube were analyzed using a computer, and the results were compared.

[0014] In the analysis, structural analysis was performed using a three-dimensional model using general-purpose finite element analysis software. However, in this analysis, thermal conditions were not considered, and only mechanical stress was considered.

From the overall diagram shown in FIG. 3 as an analytical model,
The area excluding the glass contact area and the brim-like area at the top of the tube was modeled as the analysis target area. Using this model as a basic model, we created models with different hole diameters, hole height positions, number of holes, and hole shapes, and compared the stress generated around the through holes. Table 1 shows the dimensions of each part of each model. Models marked with * in Table 1 have the same shape, but the element divisions are not the same.

[0016] The shapes of the through holes were compared between a perfect circle and an ellipse. Figure 4 shows the shape and inclination of the ellipse. Example 1 and Comparative Example 15 have the same model shape and element division, but the direction of forced displacement, which will be described later, is reversed.

[0017] During actual use, the tube rotates around the center of the tube, so the part immersed in the glass (glass contact part) receives resistance from the glass that is opposite to the rotation, causing the tube to twist. It seems that similar forces are at work. In order to express that power, in this analysis,
Constraint conditions as shown in FIG. 5 were set. The force that twists the tube is expressed by constraining the bottom of the tube in the θ direction (circumferential direction) and forcibly displacing a range of about 30 mm from the upper end of the tube side in the θ direction (direction is in the direction of the arrow in the figure). . The direction of this forced displacement is reversed only in Comparative Example 15. The forced displacement amount was set to 0.02667 radian (approximately 5 mm in the circumferential direction), but this value does not have any particular meaning and is an arbitrarily set value.

The physical property values used in the analysis were as follows.

Young's modulus: 0.447×106 kg/cm2
Poisson's ratio: 0.2

[0020]

[Stress Change in Basic Shape] Figures 6A and 6B show the stress distribution on the outside and inside of the entire basic shape model. Figure 6A
is a view of the model from the top right outside of the cylinder, and is shown from a direction that makes it easy to see the stress concentrated downward. FIG. 6B is a view of the model viewed from the lower right inside the cylinder, and is displayed from a direction that makes it easy to see the stress concentrated upward. It can be confirmed that tensile stress is concentrated in two places around the through hole. As a result of the experiment, the maximum stress value is 490 g/mm2 at the bottom and 5 at the top.
It was 20g/mm2. Figure 7 shows an enlarged view of the area around the through hole and a stress vector diagram. It can be confirmed from the vector diagram that the direction of the tensile stress is a direction tilted upward by about 45 degrees when the tube rotation direction is 0 degrees.

[0021]

[Comparative Examples 1 to 6] In order to understand the change in stress when the pore diameter was changed, Comparative Examples 1 to 6 were conducted and the tensile stresses were compared.

[0022] As a result of the experiment, the maximum stress value was 460 at the bottom.
g/mm2, and it was 500 g/mm2 in the upper part, and it was confirmed that the upper part was larger than the lower part. Furthermore, although stress tends to increase as the hole diameter increases, it was confirmed that the maximum value of the stress concentrated downward does not change much when the hole diameter becomes 35 mm or more.

[0023]

[Comparative Examples 7 to 10] In order to find out the change in stress when the height position of the hole is changed, Comparative Examples 7 to 10 were conducted and the stresses were compared. The height position of the hole is the distance from the bottom end of the tube to the center of the hole. As a result of the experiment, the maximum value of stress was 520 g/mm2 at the bottom and 535 g/mm2 at the top, confirming that it was larger at the top than at the bottom. It was also confirmed that the concentrated stress tends to increase as the height of the hole increases.

[0024]

[Comparative Examples 11 to 14] In order to find out the change in stress when the number of holes is changed, Comparative Examples 11 to 14 were conducted and the stresses were compared. In each model, the holes are spaced at equal intervals in the circumferential direction. As a result of the experiment, the maximum stress was 505 g/mm2 at the bottom and 545 g/mm2 at the top.
It was confirmed that the upper part was larger than the lower part. Furthermore, although the concentrated stress tends to increase as the number of holes increases, it was confirmed that only in the case of 4 holes, the maximum value decreased, albeit slightly, than in the case of 3 holes.

[0025]

[Examples 1 to 3 and Comparative Example 15] In order to find out the change in stress when the hole is made elliptical and the direction is changed, Examples 1 to 3 and Comparative Example 15 were conducted and the stresses were compared. The area of the oval hole in each model is approximately 1979 mm2. This value is close to the area (approximately 1964 mm2) of a perfect circular hole with a diameter of 50 mm. As described above, Example 1 and Comparative Example 15 have the same model shape and element division, but the directions of forced displacement are reversed. That is, only in Comparative Example 15, the tube was rotated in a direction opposite to that of the other Examples and Comparative Examples. As a result of the experiment, the maximum stress value was as follows except for Example 2.
It was confirmed that the upper part tends to be larger than the lower part. It was also found that changing the orientation of the elliptical hole also changed the stress concentration area. Furthermore, the concentrated stress is
In the case of Example 1, it was 410 g/mm2 at the bottom and 43 g/mm2 at the top.
It was clearly observed that in the case of Comparative Example 15, it was 675 g/mm2 at the bottom and maximum at 750 g/mm2 at the top.

FIGS. 8A and 8B show stress distributions on the outside and inside of the entire model of Example 1. FIG. 8A is a view of the model viewed from the upper right outside of the cylinder, and is displayed from a direction that makes it easy to see the stress concentrated downward. FIG. 8B is a view of the model viewed from the lower right inside the cylinder, and is displayed from a direction that makes it easy to see the stress concentrated upward. It can be confirmed that the tensile stress is concentrated at two locations around the through hole, similar to the stress distribution in the basic shape shown in FIGS. 6A and 6B. Comparing FIG. 6A and FIG. 8A, and comparing FIG. 6B and FIG. 8B,
It is clearly recognized that in Example 1, the stress concentration around the through hole is relaxed compared to the basic shape.

According to experiments, the tensile stress generated in the tube is concentrated around the through hole (at two locations) on the side surface of the tube, and it is thought that this is a structurally weak point. Therefore, it is expected that this is the starting point of cracks. In order to reduce or disperse this concentrated tensile stress, the following countermeasures are considered to be effective from the results of this analysis.

a) Decrease the pore size.

b) Lowering the height of the hole.

c) The number of holes is set to four.

d) The shape of the hole is made into an ellipse, and the long axis is tilted upward by 45 degrees when the direction of rotation of the tube is 0 degrees.

[0032] In Company A's experience, when a vented tube with an elliptical hole shape was used, troubles apparently caused by mechanical stress disappeared, and the life span of 8 to 10 months was extended to 12 to 15 months.

[0033]

Effects of the Invention The present invention provides a vented tube in a glass melting furnace feeder section, in which the through hole for internal heating of the tube is made oval, and when the rotation direction of the tube is set to 0°, the long axis of the oval This is a vented tube for a glass kiln feeder, which is characterized by being inclined upward at an angle of 0 to 90 degrees.

By forming the through hole into an ellipse shape and giving it the above-mentioned inclination, the influence of stress generated around the through hole is alleviated. Therefore, the occurrence of cracks in the vented tube is prevented, and the life of the vented tube is extended. In one case, a lifespan of 8 to 10 months was reduced to 12 months.
His life was extended to ~15 months.

[0035]

[Table 1]

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a glass oven feeder section.

FIG. 2 is a diagram schematically showing a vented tube of the present invention.

FIG. 3 is a dimensional drawing of the analysis model.

FIG. 4 is a diagram showing the shapes and inclinations of through holes in Examples 1 to 3 and Comparative Example 15.

FIG. 5 is a conceptual diagram showing constraint conditions of an analysis model.

FIG. 6A is a stress distribution diagram seen from the outside of the basic shape model.

FIG. 6B is a stress distribution diagram seen from inside the basic shape model.

FIG. 7 is a stress vector diagram of the basic shape model.

FIG. 8A is a stress distribution diagram seen from the outside of Example 1.

FIG. 8B is a stress distribution diagram seen from the inside of Example 1.

[Explanation of symbols]

1 Feeder part 2 Spout part 3 Orifice 4 Plunger 5 Vented tube 6 Through hole 7 Long axis 8 Short axis 9 Rotation direction 10 Tilt 11 Rotation axis 12 Glass

Claims (1)

[Claims] Claim 1: In a vented tube of a glass melting furnace feeder section, when the through hole for internal heating of the tube is oval and the rotation direction of the tube is 0°,
A vented tube for a glass kiln feeder, characterized in that the long axis of the ellipse is inclined upward by 0 to 90 degrees.