Agitating – Stirrer within stationary mixing chamber – Rotatable stirrer
Reexamination Certificate
1999-10-07
2001-08-07
Derrington, James (Department: 1731)
Agitating
Stirrer within stationary mixing chamber
Rotatable stirrer
C366S297000, C366S301000, C065S170000, C065S178000
Reexamination Certificate
active
06270248
ABSTRACT:
The present invention relates to a mixing apparatus for a molten substance of high temperature for mixing to homogenize a molten substance of high temperature such as molten glass flowing in a flow path defined by left and right side walls while occurrence of air bubbles is suppressed.
Further, the present invention relates to such mixing apparatus provided with a lubricant supplying means for supplying lubricant to a bearing member for supporting a rotating shaft having mixing blades and a gear box.
There has been conducted to mix molten glass produced from a furnace by arranging a mixing apparatus in a flow path so as to homogenize a glass composition or to provide a uniform temperature before a shaping operation. As such mixing apparatus, there has been known, for example, JP-A-59-130524 wherein a plurality of mixing units, each provided with a rotating shaft having radially extending mixing blades, are disposed in a side-by-side relation in a flow path for the molten glass. Specifically, an even number of pair of mixing units are arranged symmetrically with respect to the center line along the flow path so that mixing blades of adjacent mixing units are rotated in a substantially meshing state, whereby a molten substance of high temperature such as the molten glass can be mixed.
An example of a conventional mixing unit
1
is shown in
FIG. 13
wherein
FIG. 13
a
is a plan view and
FIG. 13
b
is a view from a direction of an arrow mark X in
FIG. 13
a
. As shown in the Figures, each mixing blade
2
is inclined with respect to a direction A tangential to a circle formed by the rotation of the mixing blade
2
wherein the mixing blade
2
has a working face
2
a
which inclines upward from a front part of the direction of rotation to a rear part of the direction of rotation and a working face
2
b
which inclines downward from the front part to the rear part in a direction of rotation. Further, an angle of intersection &agr; between the working face
2
a
and the rotating shaft
3
of the mixing unit
1
is 45°. The shape of an edge face of the mixing blade
2
, when viewed from the direction of the mark X (in a front view) in
FIG. 13
b
, is a rhomboid.
In the conventional mixing apparatus, the gap t between either one of left and right side walls
4
a
,
4
a
for forming a flow path
4
for the molten substance of high temperature and an outer peripheral edge
2
b
of a mixing blade
2
is determined to be 1.27-2.54 cm. However, the gap t was too narrow and bricks forming the left and right side walls
4
a
,
4
a
were eroded due to a flow of the molten substance of high temperature whereby a component of the eroded bricks entered into the molten substance of high temperature to thereby cause deterioration of the quality of a glass product produced from the molten substance of high temperature. Further, there was a large disturbance in the surface of the molten substance due to the mixing function of the blades and air bubbles were apt to enter into the molten substance whereby a percentage of defective products increased.
Further, the mixing apparatus having mixing blades
2
disposed at an angle of intersection &agr; of about 45° was insufficient to obtain a pumping function for moving the molten substance of high temperature upward or downward, and was insufficient to prevent the involvement of air bubbles to the molten substance.
In the mixing apparatus disclosed in JP-A-59-130524, a lower portion of the rotating shaft having the mixing blades of each of the mixing units is extended into the flow path for the molten glass, and an upper portion thereof is supported by a bearing member, and an upper end of each of the rotating shafts is attached with a gear wheel associated with other gear wheels. When one of the rotating shafts arranged in parallel is rotated by means of a motor or the like, the rotating shafts are rotated by the gear wheels which are associated in a manner that adjacent rotating shafts are alternately and simultaneously driven in directions reverse to each other.
It is a first object of the present invention to provide a mixing apparatus for a molten substance of high temperature which can improve the quality of glass products by preventing erosion of bricks forming left and right side walls for providing a flow path and which can sufficiently homogenize a molten substance of high temperature while air bubbles are prevented from mixing.
In a conventional mixing apparatus, lubricant such as grease is filled in the bearing member and a gear box accommodating therein associated gear wheels. However, temperature in an upper space of the flow path for molten glass is elevated to, for example, about 150° C., as a result of which the lubricant may be deteriorated or solidified, or a shaft seal portion (an oil seal) is deteriorated to cause leakage of the lubricant. Accordingly, it was necessary to supply oil frequently by manual operations.
Accordingly, it is a second object of the present invention to provide a mixing apparatus to be disposed in a flow path for a molten substance of high temperature, which can perform automatically the supply of lubricant to the bearing member and the gear box.
In order to achieve the first object, there is provided a mixing apparatus for a molten substance of high temperature which comprises a plurality of mixing units for mixing a molten substance of high temperature in a flow path for passing the molten substance, which is defined by left and right side walls, wherein the plurality of mixing units are arranged in a side-by-side relation so as to traverse the flow path, and mixing blades of adjacent mixing units are rotated in a state of substantially meshing with each other, said mixing apparatus being characterized in that the gap between a left side wall or a right side wall and an outer peripheral edge of a mixing blade is 0.04-0.1 times as much as the distance between the left and right side walls.
According to the construction described above of the present invention, the gap between a left side wall or a right side wall and an outer peripheral edge of a mixing blade is 0.04 times or more as much as the distance between the left and right side walls, whereby erosion of the left and right side walls can be prevented to minimize an adverse affect to the quality of glass products, and disturbance in the surface of molten substance due to the mixing function of the mixing blades can be reduced to thereby prevent air bubbles from mixing with the molten substance. Further, the gap between the left side wall or the right side wall and the outer peripheral edge of a mixing blade is 0.1 times or less as much as the distance between the left and right walls, whereby an unhomogenized portion of the molten substance of high temperature can be prevented from passing through, and a sufficient mixing function can be provided to obtain a desired homogenization.
According to a preferred embodiment of the abovementioned invention, the mixing units for mixing the molten substance of high temperature are arranged in such a manner that an even number of pairs of mixing units are disposed symmetrically with respect to the center line between the left and right side walls for defining the flow path for the molten substance.
Further, each of the mixing blades has a wedge shape in cross section in the observation of the blade from a direction tangential to a circle of rotation of the blade wherein a working face which inclines upward from a front part to a rear part with respect to a direction of rotation of the blade, is formed.
With the mixing blade having a wedge shape wherein a working face inclining upward is formed, a pumping function to move the molten substance upward is obtainable. The wedge-shaped mixing blade reduces an eddy current which may be produced at a rear face of the mixing blade, whereby a mixing function can be improved and occurrence of air bubbles can be reduced.
According to a further preferred embodiment of the present invention, each of the mixing blades has an angle of intersection of 55-80° between the workin
Hirabayashi Yasuhisa
Terao Ichiro
Yoshida Shouzou
Asahi Glass Company Ltd.
Derrington James
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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