KR800001515B1 - Forehearth homogenization apparatus - Google Patents

Abstract

A forehearth for feeding molten glass to a flow feeders, a set of 7 inches blenders(12,13) in diameter, a set of 4 inches homogenizers(17,18,18,20) in diameter were spaced from each other along the length of the forehearth with three evenly spaced vertically positioned elongated plates located between the set of blenders and the set of homogenizers. The particular arrangement provides a system for eliminating, to a great extent, cords at the feeder.

Description

Converter homogenizer for mixing and homogenizing molten glass

1 is a plan view of the apparatus of the present invention.

2 is a cross-sectional view taken along line 2-2 of FIG.

In the present invention, three vertical rectangular plates are located between one set of mixers and one set of homogenizers, and the homogenizers and mixers are installed at regular intervals along the length of the converters with the converters supplying molten glass to the flow transfer path. have. According to the invention it is possible to make this arrangement special and to make a system that removes most of the cords from the conveying path.

It has long been known that agitation can significantly improve the quality of glass if the glass is relatively viscous immediately before casting.

In recent years, the emphasis has been placed on reducing the weight and thickness of glass products that are produced in large quantities, such as a lidless cover, a non-recoverable beverage bottle, and the improvement of glass quality is becoming increasingly important. Streaks, cords and other defects create local vulnerabilities in glass products and therefore cannot be commercialized. By reducing striae and other defects, thickness can be reduced without loss of strength, compared to similar products where local vulnerabilities due to the presence of cords and striae have to be considered, resulting in lighter weight glass.

Background Art [0002] There is an increasing demand for relatively high quality glass that is close to the quality normally used in the manufacture of optical products, even in products made of relatively low quality glass.

The present invention can be applied to a wide range of applications, but in view of its immediate use on an actual industrial scale, it is considered that there is great applicability in a standard industrial apparatus in which almost all of the glass containers produced in large quantities in the United States are manufactured. Standard equipment accepts glass from a melting furnace where the initial components of the glass are melted and heated to a relatively high temperature to produce low viscosity glass, and a converter that cools the glass discharged from the melting furnace to increase viscosity. And a discharge bowl or spout which discharges it through the orifice in the form of agglomerates. The apparatus of the present invention is particularly suitable for replacing the end of a standard converter for agitating the glass just before delivering it to the spout.

The standard converter consists of a cooling part and an adjusting part or a homogeneous part depending on the flow order of the glass from the melting furnace to the spout. Both the cooling flame and the cooling wind are supplied to the cooling part, and the heating flame is supplied to the adjusting part, but essentially all of the cooling part is cooled so that the temperature of the entire glass flow is uniform throughout the thickness and width of the adjusting part. In the past, some stirring could be achieved at the inlet of the adjusting section by installing a rotary paddle or turbine in the melt flow of the glass. This agitation is effective to uniformize the temperature of the molten glass and reduce the temperature change, but not to significantly reduce or physically homogenize the amount of stria and cord in the glass.

The present invention relates to a method and apparatus for mixing and blending molten glass in a converter by rotating a pair of spiral blenders provided upstream of the end of the converter's transfer path to raise the glass within the working range. Downstream of the end of the converter's transfer path, a number of helical homogenizers with horizontally spaced intervals rotate to effectively push the glass below their range of operation, and a plurality of rectangular vertical plates are installed between the blender and the homogenizer, the lower edge of which Is at the bottom of the converter and extends to the full depth of the molten glass, reducing cord and other striae as the glass moves from the blender to the homogenizer.

Referring to Figs. 1 and 2, a typical flow path of the converter 11 is shown in Paul 11 and Adjustment 10. In the adjusting section 10, two mixers 12 and 13 are located. As shown in the figure, the adjuster 10 is about 26 inches wide and has a glass about 12 inches deep therein. Blenders 12 and 13 are about 7 inches in diameter.

The vertical axes of blenders 12 and 13 are located about 6.5 inches from the side wall of the adjuster. In the figure it can be seen that the glass flows from the left side of the figure to the right side while flowing out of the glass in the form of lump from the tool (위치한 口) located under the opening formed in the bottom of the converter. Directly above the tool 14 is a plunger 15 which serves to control the formation of lumps. Tube 16 surrounds plunger 15, which is rotated to keep the glass near the tool at a relatively uniform temperature.

Upstream of tube 16 there are four homogenizers 17, 18, 19, and 20. In one example, the homogenizer is 4 inches in diameter. Homogenizer 17-20 rotates in the direction of the arrow shown in FIG. Blenders 12 and 13 also rotate in the direction of the arrows shown in FIG. Between the blender and the homogenizer are plates 21, 22 and 23 each 8 inches long. The backplate is supported by a bar 24 extending across the width of the converter and is shown in detail in FIG. 1. The plates are rectangular, spaced apart from each other, and the same distance from the mixer and homogenizer. The bottom end of the tube abuts the bottom of converter 25 and provides the shear face of the moving glass with the sidewalls of the adjacent converter. These plates are fixed and these plates are constructed of materials that can withstand glass temperature and erosion of moving glass. The mixer and homogenizer is a spiral mixer, as shown in the figure, spaced 2 " -3.5 " enough to prevent excessive glass shear from the bottom of the converter.

Applicants have found that the use or positioning of vertical plates calibrated to converters increases shear stress and reduces cords.

As mentioned above, low shear stress values do not produce fine bubbles. As shown in the figure, an equal flow path is used between the plates to minimize the variation of the mixing effect resulting from the asymmetry between the sides. In model converters, we used 4 inch, 8 inch, and 12 inch length plates for different layouts.

When the plate was placed between the blender and the homogenizer, it had some effect on mixing the cords in all batches. However, 4-inch plates are less effective than cords appearing at the top or middle of the converter flow path than 8-inch or 12-inch plates. If the plate is positioned between the blender and the homogenizer, the mixing effect on all cords of the upper and middle centers is improved. However, there is no significant change in the midside and bottom cords and these are affected by the mixing method. It has been found that 8-inch plates are more effective than 12-inch plates for mixing cords, mainly because 8-inch plates have less resistance to flow around the stirrer than 12-inch plates. The introduction of the holding plate in the converter increases the resistance of the glass flow, and for this reason it is necessary to increase the glass level to about 1-1 / 2 inch in the economy to maintain the glass level at 12-inch at the end of the converter. It should be noted that this depends on the actual flow rate through the converter.

In a special arrangement in which the blender is to move the glass upwards and the homogenizer is to move the glass downwards, a lot of glass is moved from the blender to the homogenizer in its upper range where the plates are located. In this way the plate effectively reduces the cord present on the glass.

)시킨다. 그러나 이러한 배합기의 결점이 있는 반면, 이 결점은 낮은 각속도에서 작용이 가능하며 혼합 효과를 개선시켜 준다는 점으로 보완된다. 일반적으로 작용 반경이란 교반기의 회전이 유체에 유의한 영향을 미치는 교반기로 부터 가장 먼 반경거리를 말한다. 혼합되는 모든 유체에서 교반기 작용은 작용반경과 정지된 전로 표면과의 사이의 상호 작용을 혼합시켜 주는 것이다. 작용 반경이 충분히 중첩되지 않는 경우 교반기 주위에 짧은 순환이 일어나게 되어 코드가 혼합되지 않고 교반기 넘어로 유동하게 된다. 본 발명에서 바람직하지 못한 혼합편차를 감소시키기 위해 교반은 전로의 종(從) 중심선에 대해 대칭으로 이루어져야 한다는 것을 알았다. 비대칭성 교반은 순환범위를 짧게 한다. 대칭교반 설비는 측면사이의 편차를 최소로 해주며 짧은 순환을 감소시켜 준다. 하나의 교반배치에서 혼합되지 않은 유체가 또 다른 교반배치의 취약지역으로 통과될 가능성을 감소시키기 위해 연속되는 교반장치는 상이한 것을 사용한다. 아마도 서로 다른 교반장치를 사용하여 대칭성을 계속 유지하는 가장 쉬운 방법은 잇달은 교반장소에 상이한 짝수의 교반기를 배치시키는 것이다. 이들 교반장치의 작동은 전로의 종중심선에 대해 대칭어야 한다.Several factors should also be considered. 7-inch diameter blenders are effective at 20 rpm because they are large in size. The mixing effect of a 7-inch diameter compounder with a 4-inch homogenizer increases the radius of action, but the range of action of the compounder is greatly reduced when the circulation of fluid around the compound is short. 7-inch diameter blenders blow air at lower angular velocities than 4-inch diameter blenders.

) However, while there is a drawback of such a blender, this drawback is complemented by being able to work at low angular velocities and improving the mixing effect. In general, the working radius refers to the radial distance farthest from the stirrer, where the rotation of the stirrer has a significant effect on the fluid. In all fluids mixed, the stirrer action mixes the interaction between the radius of action and the stationary converter surface. If the radius of action does not overlap sufficiently, a short circulation occurs around the stirrer and the cord flows over the stirrer without mixing. It has been found that agitation should be symmetrical about the longitudinal centerline of the converter in order to reduce undesirable mixing deviations in the present invention. Asymmetrical agitation shortens the circulation range. Symmetrical stirring equipment minimizes side to side deviations and reduces short cycles. In order to reduce the likelihood that unmixed fluid in one stirring batch will pass into the vulnerable area of another stirring batch, successive stirring devices use different ones. Perhaps the easiest way to maintain symmetry using different stirrers is to place different even numbers of stirrers in subsequent stirrers. The operation of these agitators should be symmetrical about the longitudinal center line of the converter.

)은 물론 미세한 기포를 유발하는 전단을 막기위해 교반기의 회전속도에는 한계가 있다.Another consideration is the possibility of generating a shear that causes microbubbles by stirrer operation. The formation of fine bubbles is related to shear stress or shear deformation or other shear-related action. In view of this, care must be taken with the shear that accompanies the mixing of the glass. Air blowing in the spiral mixer of the present invention (取

), Of course, there is a limit to the rotational speed of the stirrer to prevent shear that causes fine bubbles.

Another important thing in successfully performing the homogenization method is to avoid fluctuations in the glass level in the conveying path and to maintain a suitable glass level on the stirrer.

As described in the appended claims, the present invention relates, in particular, to the removal of cords from moving glass in a transfer converter by a combination of blender, homogenizer and stationary plate.

Claims (1)

A pair of blenders located laterally upstream of the end of the converter's transfer path that effectively lifts the glass within their range of operation; A plurality of homogenizers positioned between the blender and the conveying path to effectively push the glass downwards within their working range, and installed at equal intervals in the transverse direction with respect to the flow of molten glass in the converter; It reduces the movement of the glass from the blender range to the homogenizer range and sends the cordless glass to the transfer path, arranged in a direction parallel to the flow of glass in the converter and in the molten glass between the blender and the homogenizer. An apparatus for mixing and blending molten glass in a converter, consisting of a number of rectangular vertical plates impregnated.

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