Textiles: manufacturing – Thread finishing – Surface modification of running length
Reexamination Certificate
1999-10-25
2001-07-03
Vanatta, Amy B. (Department: 3765)
Textiles: manufacturing
Thread finishing
Surface modification of running length
C028S221000, C028S267000, C019S0660CC
Reexamination Certificate
active
06253431
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to systems which can be used to open a tow of fibers such that the resulting “opened tow” of fibers has a shape useful in the production of absorbent structures, and more particularly to an air opening jet apparatus for use in such systems.
BACKGROUND OF THE INVENTION
Many types of filaments, fibers and yarn (collectively “fibers”) are sold as a “tow” in which a plurality of such fibers are compressed together, optionally with crimping, by methods known to those skilled in the art in order to maximize the content of the packing systems, for example, bales, by which such tows are sold and delivered to users of tow. Before use, such users generally “open” such tow, separating the compressed fibers by a distance greater than that in the compressed state. Numerous methods and devices for opening tows are known and described in the art. Examples include U.S. Pat. Nos. 3,282,768, 3,099,594, 4,522,616, 2,794,480, 3,032,829, 5,591,297 and 5,203,757 whose teachings are incorporated herein by reference. While such devices have found utility in various applications, such devices typically produce “opened” tows which were substantially circular in cross-section, for example, tows used to make smoke filters or writing instrument reservoirs. However, for other applications a rectangular shape is preferred; for example, absorbent structures which are intended for use in personal care products such as diapers, bandages, hygiene pads and similar absorbent products. For such uses a shape that has a substantially rectangular cross-section is preferred.
It is also known to use, in systems of the foregoing types, air jets which open the tow and form it into a rectangular shape for use in tobacco filter rods and the like, as disclosed in U.S. Pat. Nos. 4,468,845 and 4,435,239. One of the significant advantages asserted for these systems is the fact that the air opening jet employed in the system is designed to operate at very low air pressures (e.g. less than 3 psi), which is said to eliminate the need for the large capital investment in expensive air compressing and piping facilities normally associated with air opening or “blooming” systems. This low pressure air is utilized to move the tow through the air opening jet, during which the tow is opened, and then through a bustle assembly in which the opened tow is decelerated and retarded in the bustle assembly to obtain the desired opening and density of the tow. This deceleration and retarding of the tow is obtained by an adjustable tension arrangement for engaging the tow, and more particularly by a flat, imperforate “tension” plate that is pivotally mounted at one of its ends within the bustle assembly, and a relatively complex mechanical arrangement for adjusting the movement of the pivoted tension plate toward and away from the tow to thereby vary the tension force applied to the tow by the tension plate.
SUMMARY OF THE INVENTION
In accordance with the present invention, an air opening jet apparatus is provided for use in a system for opening a thin, relatively wide tow of textile filaments held together by crimping and forming the opened tow into a predetermined shape suitable for use as an absorbent structure for personal care products. The air opening jet apparatus includes a housing having an inlet opening for receiving a partially opened tow and having a configuration corresponding generally to the shape of the partially opened tow. The housing also has an outlet opening through which the tow exits the housing and this outlet opening has configuration corresponding generally to the predetermined shape.
An air jet is formed within the housing adjacent the inlet opening thereof to create a venturi which moves the tow through the air opening jet apparatus and which also further opens the tow, and a source of compressed air communicates with the air jet to provide carrier air for moving the tow through the air opening jet apparatus.
A forming chamber is provided within the housing and downstream of the air jet that includes a gradually increasing cross-sectional area in the direction of flow of the tow that corresponds to the predetermined shape, the airjet being disposed within the housing to cause the tow to be fully opened and to substantially fill the forming chamber as it moves therethrough.
An accumulating chamber is located within the housing downstream of the forming chamber that is constructed and arranged to permit the opened tow to accumulate within the accumulating chamber and be withdrawn from the housing at different flow rates through the housing outlet opening in the predetermined shape. The accumulating chamber includes at least one perforated plate disposed in the path of the tow and the carrier air moving therethrough to cause the tow to engage the perforated plate and to cause at least some of the carrier air to pass through the perforated plate.
A control valve is provided for maintaining the flow of the carrier air at a level that will cause at least the portion of the carrier air to pass through the perforated plate and urge the tow into frictional engagement with the perforated plate with sufficient force to retard the movement of the tow through the accumulating chamber and cause the tow to accumulate in the accumulating chamber.
In the preferred embodiment of the present invention, the accumulating chamber may include a second perforated plate located in spaced relation to the first above mentioned perforated plate, and the tow moves between the perforated plates and is urged into engagement therewith by the carrier air passing through both the perforated plates. Finally, in the preferred embodiment of the present invention, the predetermined shape of the outlet opening in the housing is rectangular.
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Ames Todd
Kenley Ricky
Powers Edward J.
West William
Wygand William T.
Celanese Acetate LLC
Kennedy Covington Lobdell & Hickman LLP
Vanatta Amy B.
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