Glass manufacturing – Fiber making apparatus – With specified bushing – tip – or feeder structure
Reexamination Certificate
2001-11-09
2004-08-24
Griffin, Steven P. (Department: 1731)
Glass manufacturing
Fiber making apparatus
With specified bushing, tip, or feeder structure
C065S492000, C373S028000
Reexamination Certificate
active
06779366
ABSTRACT:
TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION
This invention relates to a bushing assembly/support structure arrangement wherein the bushing assembly is adapted to receive a molten material and includes a plurality of nozzles through which the molten material passes prior to being attenuated into continuous fibers.
BACKGROUND OF THE INVENTION
In the manufacture of continuous glass fibers, glass forming batch ingredients are added to a melter where they are heated to a molten condition. The molten glass travels from the melter to one or more bushing assemblies by way of a glass delivery system, e.g., a channel and a forehearth. Each bushing has a number of nozzles or tips through which streams of molten glass flow via gravity. Those streams are mechanically drawn to form continuous glass fibers by way of a winder or like device.
A prior art bushing assembly is illustrated in FIG.
1
. It comprises a bushing main body
10
having a plurality of side walls
11
(only one of which is illustrated) and a tip plate
12
extending between the side walls
10
. The tip plate
12
includes the nozzles
12
a
through which the streams of molten glass flow via gravity. A first support rail
20
is coupled to a first side wall of the bushing main body
10
. A second support rail (not shown) is coupled to a second, opposing side wall of the main body
10
. A plurality of C-shaped support brackets
30
(only one of which is illustrated in
FIG. 1
) are coupled to the first and second support rails
20
and the side walls
11
of the main body
10
. Each support bracket
30
comprises outer members
30
a
and
30
b
, which are integral with and extend generally orthogonal to a generally horizontal intermediate member
30
c
. Ends of the outer members
30
a
and
30
b
opposite the ends integral with the intermediate member
30
c
are coupled to a corresponding support rail and main body side wall. A like number of support straps
40
(only one of which is illustrated in
FIG. 1
) are coupled to and extend from a bushing frame (not shown) and provide upwardly directed forces for supporting the bushing assembly. To insulate the support straps
40
and the bushing frame from electrical and thermal energy flowing through the main body
10
, an electrically and thermally non-conductive bar
50
is provided between each support bracket
30
and corresponding support strap
40
. Hence, each support strap
40
applies its upwardly directed holding force against a corresponding insulator block/support bracket combination.
It is desirable for all bushing assembly nozzles to be positioned in generally the same horizontal plane. Typically, a plurality of cooling fins (not shown) are provided below the tip plate and extend between rows of the tip plate nozzles. Heat is radiantly and convectively transferred from the nozzles and the glass streams to the fins. If one or more first nozzles are repositioned closer to a corresponding fin, such as due to deformation of the tip plate, the heat transfer rate away from those first nozzles increases. An increase in the heat transfer rate away from a given nozzle results in a decrease in the glass flow rate through that nozzle. A reduction in glass flow rate through a nozzle results in a corresponding fiber being formed having a reduced diameter. Fibers formed having reduced diameters are more likely to break. Breakage of a single fiber during a fiber forming operation results in the operation failing and being shutdown. Consequently, operating costs are increased and productively is decreased.
The bushing assembly illustrated in
FIG. 1
is typically formed from an alloy of platinum or a like material and is routinely operated at temperatures exceeding 2200° F. At such high operating temperatures and after only a limited amount of time in production, one or more support brackets
30
either deform or separate from a corresponding support rail and main body side wall. Deformation or separation of a support bracket results in a portion of the perimeter of the bushing assembly main body being inadequately supported. This, in turn, can result in a portion of the tip plate being distorted. Tip plate distortion results in one or more nozzles being displaced from a nominal horizontal plane, in which all nozzles are initially positioned. As noted above, nozzle displacement can result in glass flow rate changes. Once a significant glass flow rate change has occurred at one or more nozzles, the bushing assembly must be replaced.
The dimension from the tip plate outer surface to an inner bearing surface on a support bracket intermediate member
30
c
should be the same for each support bracket. If the support brackets are positioned relative to the tip plate inconsistently, installation of the bushing assembly within the bushing frame/support strap assembly becomes difficult and time consuming. This is because one or more support straps must be reconfigured or machined to compensate for the incorrectly positioned support brackets such that the bushing assembly tip plate is positioned in a generally horizontal plane. Because each support bracket is manually positioned and welded to its corresponding support rail and main body side wall, it is difficult to produce a bushing assembly having support brackets consistently positioned relative to the tip plate.
It is desirable to have a bushing assembly/support structure arrangement where adequate support is provided for a bushing assembly main body over an extended period of time so as to increase the useful life of the bushing assembly. It is also desirable to have a bushing assembly/support structure arrangement where the bushing assembly can be easily installed within a bushing frame/support strap assembly.
SUMMARY OF THE INVENTION
With the present invention, an improved bushing assembly/support structure arrangement is provided. The bushing assembly comprises a bushing main body having, in one embodiment, first and second support rails fixedly coupled to opposing sides of the main body. Each support rail has first and second planar surfaces, which define a substantially L-shaped body. The support rails are accurately positioned vis-a-vis an outer surface of a tip plate. A first planar surface of each support rail is then fixedly coupled to a corresponding side wall of the main body. The bushing assembly further comprises a plurality of brackets. Each bracket comprises an intermediate member having a substantially planar face fixedly coupled along substantially its entire length to a corresponding main body side wall. Portions of each support rail extending between first and second leg members of a corresponding bracket function as bearing surfaces for corresponding support straps extending from a bushing frame. Because each support rail is fixedly coupled along substantially its entire length and each bracket is fixedly coupled along substantially the entire length of its intermediate member, each support strap contact region on the first and second support rails is robust and unlikely to distort or sag over extended periods of usage. Accordingly, the time period between bushing assembly changeovers is increased resulting in lower glass fiber production costs.
In accordance with a first aspect of the present invention, a bushing assembly is provided for containing a molten mineral material from which fibers can be attenuated. The bushing assembly comprises a bushing main body comprising at least first and second side walls and a tip plate extending between the side walls. The tip plate contains a plurality of orifices through which molten mineral material flows so as to be attenuated into fibers. The bushing assembly further comprises a first support rail coupled to the main body first side wall and at least one first bracket having an intermediate member coupled to the main body first side wall.
The first support rail may comprise first and second substantially planar surfaces integral with one another and defining an L-shaped body. The support rail first planar surface may be coupled to the main body first sid
Bemis Byron L.
Morgan Gregory L.
Sullivan Timothy A.
Dottavio James L.
Eckert Inger H.
Griffin Steven P.
Hug Eric
Owens Corning Fiberglas Technology Inc.
LandOfFree
Bushing assembly/support structure arrangement does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bushing assembly/support structure arrangement, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bushing assembly/support structure arrangement will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3310839