Information
-
Patent Grant
-
6253431
-
Patent Number
6,253,431
-
Date Filed
Monday, October 25, 199924 years ago
-
Date Issued
Tuesday, July 3, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Kennedy Covington Lobdell & Hickman, LLP
-
CPC
-
US Classifications
Field of Search
US
- 028 283
- 028 282
- 028 281
- 028 220
- 028 221
- 028 262
- 028 263
- 028 264
- 028 265
- 028 267
- 028 271
- 028 273
- 028 274
- 028 276
- 028 248
- 019 66 T
- 019 66 R
- 493 44
- 493 50
- 493 48
-
International Classifications
-
Abstract
The invention provides an air opening jet for use in a process for making a rectangular structure made from a tow of fibers, such air opening jet including a housing, an air jet for moving the tow through the housing and opening the tow, and an accumulating chamber that includes at least one, and preferably two, perforated plates located in the path of the moving tow, and an air control arrangement for controlling the flow of air so that the moving tow is urged into engagement with the perforated plates to retard movement of the tow and cause it to properly accumulate in the accumulation chamber.
Description
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.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a diagrammatic illustration of a typical tow opening system of the type in which the air opening jet of the present invention may be used;
FIG. 2
is a perspective view of a preferred embodiment of the air opening jet of the present invention;
FIG. 3
is a side elevational view, partially in section, illustrating the air opening jet illustrated in
FIG. 2
;
FIG. 4
is a plan view of the housing of the air opening jet illustrated in
FIG. 2
;
FIG. 5
is an elevation view illustrating the outlet opening in the housing;
FIG. 6
is an elevation view of one of the side plates of the housing; and
FIG. 7
is an elevation view of the inlet opening of the housing.
DETAILED DESCRIPTION OF THE INVENTION
The term “fiber” as used herein means a filament, fiber or yarn of any material whatsoever; for example, cellulose acetate and triacetate, polyester, polyamide, polyolefin and similar polymeric substances.
The term “tow” as used herein means a plurality of fibers compressed together, optionally with “crimping” as such term is used and understood in art, by methods known to those skilled in the art in order to maximize the content of packaging systems by which such tows are sold and delivered, or to facilitate the transport of such plurality of fibers from one point to another point, for example, within a manufacturing facility.
The terms “rectangular” and “substantially rectangular” as used herein, are to be understood as meaning a structure have a generally rectangular cross-section with possible slight defects, for example, rounded corners and a slight bowing or indentation along a side.
The fibers comprising the tow may be made from any natural or synthetic substance, or mixture and/or blends thereof, including polyesters, polyamides, cellulose acetate and triacetate (collectively, an “acetate” tow), polypropylene oxide, polyethylene sulfide, liquid crystalline polymeric substances capable of being formed into fibers, polyamides, silk, wool, cotton, rayon, polyolefins, polyacrylates, polymethacrylates, and similar substances which can be made into fibers. Such fibers may or may not have a “finish” applied to them, depending upon their application. Generally, an external finish is applied to such fibers so as to facilitate transport, although “internal” finishes, contained in the material used to form the fiber, may also be used and such fibers are included within the scope of the invention. In addition, the fibers of the tow may be of any denier, tex, diameter or other cross-sectional or cross-section related size designation suitable for producing tow.
The terms “banding jet” and “air banding jet” are used to signify a first tow opening device which utilizes air to spread a tow in a direction perpendicular to the direction of travel. The “banding jet” is different and distinct from the “opening jet” or “air opening jet” also described herein.
While the present invention may have a wide variety of tow opening applications, it has been found to be particularly useful in opening a tow made of acetate fibers, polyester fibers, polyolefin fibers and polyamide fibers, and mixtures thereof. For example, an acetate tow may consist of about 2,500 to about 25,000 fibers having an individual denier of from about 1 to about 10, preferably of from about 3 to about 6. The total denier for the entire tow, that is the assemblage of from about 2,500 to about 25,000 fibers, is thus from about 2,500 to about 250,000. Acetate tows are generally of about 10,000 to about 20,000 fibers of individual denier of about 3 to about 6, giving rise to a tow having a total denier of about 30,000 to about 120,000.
The fibers of a tow should be uniformly or substantially uniformly distributed across the width/cross-section of the crimped tow bundle or band. This uniform fiber distribution is important to the process of opening a tow into a rectangular or substantially rectangular shape, and the more nearly uniform distribution of fibers the easier it will be to produce a rectangular or substantially rectangular opened tow. Crimped and baled tows having a variety of width/cross-sections may be used in accordance with the invention, for example, about 25 mm (millimeters) to about 75 mm in width, preferably from about 40 mm to about 60 mm, and from about 1 mm to about 7 mm in height or thickness, preferably from about 2 to about 5 mm, with typical the dimensions being about 50 mm wide and about 3 mm thick.
As previously mentioned, an external finish may be applied to each fiber in a tow, such finish being in an amount from about 0.3% to about 5% by weight of the fiber bundle, preferably from about 0.5% to about 2.0%.
The tows used in practicing the invention are generally “crimped tows” as the term is used and known to those skilled in the art. Crimping is done at about 5 to about 30 crimps per inch of uncrimped tow, preferably of from about 20 to about 25 crimps per inch of uncrimped tow.
While it is to be understood that the present invention may have applications in a variety of tow opening systems, one typical system in which the present invention finds particular application is illustrated diagrammatically in
FIG. 1. A
tow
14
may initially be fed through a conventional set of guides (not shown) to flatten and orient the tow
14
. The tow is then fed to a banding jet
130
of conventional design. The banding jet evenly spreads the tow band in the direction perpendicular to the tow processing direction. Generally, the air banding jet
130
used in these preferred embodiments can be any air banding jet known in the art, for example, as described in U.S. Pat. No. 3,226,773, or in co-pending U.S. patent application Ser. No. 09/219,818, filed Dec. 23, 1998, whose teachings are incorporated herein by reference. The tow
14
is then fed to a pre-tension roller assembly
40
and is compressed between metal roller
42
and rubber roller
44
of tension roller assembly
40
so as to stretch the tow and deregister and separate the tow fibers. Within tension roller assembly
40
, roller pressure, the force applied to the tow by the rollers
42
and
44
, is from about 1 to about 25 psi, preferably from about 5 to about 15 psi. Within device
40
as illustrated in
FIG. 1
, the metal roller is element
42
(top roller) and the rubber roller is
44
(bottom roller).
After emerging from assembly
40
, the tow is fed to roller assembly
60
comprising a driver metal roller
62
and a rubber roller
64
, said metal roller
62
having circular grooves or threaded or being a flat metal roller. During its traverse from assembly
40
to assembly
60
, the tow is stretched, the stretching being accomplished by the drag associated with the nip pressure between rolls
42
and
44
. The nip pressure between the rollers of assembly
60
is from about 1 to about 40 psi, preferably from about 20 to about 30 psi.
After emerging from assembly
60
, tow
14
is passed by an optional first static eliminating bar
100
to remove any static charge which might be present on tow
14
and which might interfere with subsequent operations necessary in the formation of an absorbent structure.
After emerging from assembly
60
, the tow is fed to roller assembly
70
comprising a driven metal roller
72
and a rubber roller
74
, said metal roller
72
having circular grooves, or threaded, or being a flat metal roller. During its traverse from assembly
60
to assembly
70
, the tow is stretched, the stretching being accomplished by driving the metal roller
72
at a rotational speed faster than driven roll
62
. The rotational speed of roll
72
is between 20-60 percent faster than roll
62
, preferably 30-50 percent. Each of the roller assemblies
40
,
60
&
70
, are conventional and well known; they include an arrangement for applying a pressure on one of the rolls in the assembly to urge the two rolls in the assembly into engagement with one another at a pre-determined pressure level. These conventional assemblies may apply the pressure pneumatically, hydraulically or electrically, but pneumatic control is preferred.
The nip pressure between the rollers of assembly
70
is from about 1 to about 40 psi, preferably from about 20 to about 30 psi.
The tow emerging from assembly
70
is referred to hereafter as tow
14
. The grooves or threads of roller
64
and
74
are of a design or orientation known to those skilled in the art of tow processing or opening. The fibers which emerge from assembly
70
are substantially deregistered or opened, suitable for further opening or forming into a lofty rectangular structure.
Substantial deregistration or blooming means that 90% or more, preferably 95% or more, of the fibers constituting the rectangular structure or rectangular tow are spaced apart by a distance greater than the distance between the fibers when the tow
14
was removed from bale
12
.
After emerging from assembly
70
, tow
14
is passed by an optional static eliminating bar
101
to remove any static charge which might be present on tow
14
and which might interfere with subsequent operations necessary in the formation of an absorbent structure.
After anti-static treatment, tow
14
is transported to an optional liquid additive assembly
80
which includes a liquid holding tank, a metering pump
84
and liquid dispenser applicators
86
within assembly
80
for dispersing liquids onto tow
14
. The liquid dispersal applicators
86
may be spray nozzles, disk applicators, rotating brush applicators, wick contact rolls and similar devices of conventional design known to those skilled in the art. Liquids which can be dispersed onto tow
14
include water; hydrophilic liquids such as alcohols, glycols, dimethyl sulfide, ketones, ethers and similar substances; plasticizers such as Fiberset 100 or Fiberset 200 (Henkel Corporation, Cincinnati, Ohio); surfactants; and solutions containing plasticizers, surfactants and similar substances known to those skilled in the art. The liquid or solutions can be applied to either or both sides of tow
14
as it passes through assembly
86
, and additionally can be applied in specific patterns of multiple liquids to create unique effects for transferring or storing liquids in an absorbent composite structure in which the rectangular tow
14
is included.
After emerging from the air opening jet
240
, the tow
14
is delivered to optional assembly
120
where solid substances, for example, superabsorbent polymers (SAP), glues, adhesives, fragrances, wood pulp, deodorizers, anti-microbial agents and similar substances can be applied to tow
14
by equipment such as a streamout feeder fabricated by Solids Flow, Inc. of Fort Mill, S.C. For example, in the preparation of diapers containing SAP, the SAP may be delivered as a powder or a slurry vertically downwards on to tow
14
. The low density, open, rectangular tow band structure exiting air jet
240
permits particles of solids to evenly distribute within the tow fiber structure. The fiber structure with evenly distributed solid particles can quickly be delivered to a subsequent process so that solid particle containment is achieved. Liquid addition from assembly
80
also enhances solids containment.
After the addition of solid substances by assembly
120
, tow
14
is delivered to an optional speed delivery assembly
90
comprising, among other things, a driven roller
92
and a roller
94
, either or both of which may have a rubber or metal surface for contact with tow
14
. Driven roller
92
controls the overall operation of the process and the speed of the tow
14
as it is delivered to another process such as a diaper or absorbent composite forming machine. In general, driven roller
92
and driven roller
72
are operated at speeds such that the surface speed ratio (
72
/
92
) is from about 1.0 to about 3.0, preferably 1.8 to 2.2.
The linear speed of roll
92
is typically controlled by the line speed of a diaper or absorbent composite forming process to which the lofty rectangular tow structure is being fed.
In the preferred embodiment tow
14
is delivered directly to a diaper or absorbent composite forming process without the use of delivery speed assembly
90
. In this embodiment the diaper or absorbent composite process acts as the delivery or takeaway speed control. The tow band structure with solids and applied liquids is nipped between rollers or wrapped around a driven single roller and pulled away from the air jet
240
. Tissues or other webs can be introduced to encapsulate the fiber solids structure.
Additional optional static eliminating bars, elements
102
and
103
, may be positioned between the air opening jet
240
and the liquids addition assembly
80
, and after the air opening jet
240
. Static eliminating bars
100
,
101
,
102
, and
103
can facilitate controlling the processability of tow
14
by limiting static electricity and controlling the shape of the rectangular structure of tow
14
. Additional static eliminating bars may be employed as required and are recommended when the moisture content in the environment is low. Such additional anti-static bars may not only be located after assemblies
60
,
70
and
80
, but also between assemblies
60
and
40
,
40
and
130
, and
120
and
90
. Preferred embodiments have at least static eliminating bars
100
,
101
, and
102
.
The air opening jet
240
of the present invention includes a housing
242
that is formed, at one of its ends, with an inlet opening
244
. As best seen in
FIG. 7
, the inlet opening
244
has a generally rectangular configuration that corresponds generally to the shape of the partially opened tow
14
which is received in the inlet opening
244
as described above. The housing
242
also includes an outlet opening
246
which, as best seen in
FIG. 5
, also has a rectangular configuration that corresponds to the desired shape of the tow leaving the air opening jet apparatus
240
.
An air jet, generally indicated by the reference numeral
248
, is formed adjacent the inlet end of the housing
242
, and it includes a source of compressed air
250
and a conventional control valve
252
for regulating the flow of compressed air from the compressed air source
250
to an air manifold,
254
through which the compressed air is delivered to jet orifices
256
which form a conventional jet of air for moving the tow
14
through a central passageway
258
in the housing
242
as will be explained in greater detail presently. As best seen in
FIG. 3
, the passageway
258
has a gradually increasing cross-sectional area in the direction of movement of the tow
14
so as to provide a forming chamber
260
downstream of the air jet
248
, and this forming chamber
260
also preferably has a generally rectangular configuration that corresponds to the rectangular shape of the tow
14
.
An accumulating chamber
262
is located adjacent the outlet end of the housing
242
and downstream of the forming chamber
260
, and the accumulating chamber
262
has a vertical dimension which is greater than the outlet opening
264
of the forming chamber
260
, and it also is preferably formed with a rectangular configuration that will permit the opened tow
14
passing into the accumulating chamber
262
from the forming chamber
260
to accumulate within the accumulating chamber
262
and ultimately be withdrawn from the housing
242
through the outlet opening
246
at different flow rates and in the preferred rectangular shape of the tow
14
.
As best seen in
FIGS. 3 and 4
, a pair of plates
268
, each having a large number of perforations
270
therein, are disposed in the accumulating chamber
262
and in the path of the tow
14
as it exits the forming chamber
260
and enters the accumulating chamber
262
. The plates
268
are fixed in place within the accumulating chamber
262
by a plurality of bolts
272
that maintain the plates
268
in fixed positions within the accumulating chamber
262
.
The housing
242
also includes a pair of side plates
274
which extend along both sides thereof (see
FIG. 7
) to enclose the sides of the accumulating chamber
262
and the forming chamber
260
, and each of the side plates
274
is formed with a plurality of perforations
276
which are located generally at a position where the carrier air leaves the forming chamber
260
and enters the accumulating chamber
262
, whereby some of the carrier air can be discharged through the perforations
276
.
In operation of the air opening jet apparatus
240
, compressed air from the compressed air source
250
flows to the air jet
248
at a flow rate controlled by the control valve
252
, and the jet of air formed by the orifices
256
will move the tow
14
through the forming chamber
260
. As the tow
14
is moved through the forming chamber
260
by the carrier air, the carrier air will partially open and expand the tow
14
so that it gradually increases in cross-sectional area in conformity with the gradually increasing cross-sectional area of the forming chamber
260
. When the tow exits the forming chamber
260
and enters the accumulating chamber
262
, it first opens even further to correspond to the vertical distance between the upstream ends of the perforated plates
268
(see FIG.
3
), and the tow
14
engages the inner surfaces of the perforated plates
268
which are disposed in the path of the tow
14
.
While some of the carrier air may be discharged through the perforations
276
in the side plates
274
, a substantial portion of the carrier air moves the tow
14
through the spacing between the perforated plates
268
and passes outwardly through the perforations
270
in the plates
268
. In so doing, the air passing outwardly through the perforations
270
urges the tow
14
into frictional engagement with the facing inner surfaces of the perforated plates
268
, and this frictional engagement creates a braking action on the tow
14
which retards the movement of the tow
14
through the accumulating chamber
262
and causes the tow to density and accumulate in the accumulating chamber
262
at a density greater than it had in the forming chamber
260
, after which the opened and now densified tow
14
exits the accumulating chamber
262
through the outlet opening
246
at different flow rates.
It is important that the tow
14
which exits through the outlet opening
246
has a desired and uniform density throughout the generally rectangular shape of the tow
14
, and the present invention provides a unique and very desirable method of properly controlling the density of the exiting tow
14
. More specifically, it will be apparent that the flow rate of the carrier air will determine the retarding or braking action applied to the tow
14
as it passes between the perforated plates
268
. If the flow rate of the carrier air is increased, the carrier air passing outwardly through the perforations
270
in the plates
268
will urge the tow
14
into engagement with the plates
268
with a greater force, and will thereby increase the retarding or braking action that is applied to the tow
14
. Conversely, if the flow rate of the carrier air is decreased, there will be a smaller braking action applied to the tow
14
.
Therefore, virtually infinite regulation of the braking action is obtained in the present invention by the simple expedient of operating the control valve
252
to provide a flow of carrier air that will provide the desired braking action imposed on the tow
14
, and thereby control the density of the tow
14
as it leaves the housing
242
.
Although it will be appreciated that the actual flow rate of the carrier air will vary from application to application depending on a number of factors, it has been found in operation of a prototype of the present invention that an air pressure of about 40 psi provides a desirable density of the tow
14
consisting of 0.004 grams/cm
3
exiting through an outlet opening having a width of 20 centimeters and a height of 2.5 centimeters.
It will, therefore, be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.
Claims
- 1. An air opening jet apparatus 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, comprising:(a) 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, and having an outlet opening through which said tow exits said housing and having a configuration corresponding generally to said predetermined shape; (b) an air jet formed within the housing adjacent said inlet opening thereof to create a venturi which moves the tow through the air opening jet apparatus and which also further opens the tow; (c) a source of compressed air communicating with said airjet to provide carrier air for moving said tow through said jet apparatus; (d) a forming chamber 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 said predetermined shape, said air jet being disposed within said housing to cause said tow to be fully opened and to substantially fill said forming chamber as it moves therethrough; (e) an accumulating chamber located within said housing downstream of said forming chamber that is constructed and arranged to permit said opened tow to accumulate within the accumulating chamber and be withdrawn from said housing at different flow rates through said housing outlet opening in said predetermined shape, said accumulating chamber including at least one perforated plate disposed in the path of said tow and said carrier air moving therethrough to cause said tow to engage said perforated plate and to cause at least some of said carrier air to pass through said perforated plate; and (f) a control valve for maintaining the flow of said carrier air at a level that will cause at least said portion of said carrier air to pass through said perforated plate and urge said tow into frictional engagement with said perforated plate with sufficient force to retard the movement of the tow through said accumulating chamber and cause said tow to accumulate in said accumulating chamber.
- 2. An air opening jet apparatus as defined in claim 1, wherein said accumulating chamber includes a second perforated plate located in spaced relation to said at least one perforated plate, and wherein said tow moves between said perforated plates and is urged into engagement therewith by said carrier air passing through both said perforated plates.
- 3. An air opening jet apparatus as defined in claim 1, wherein said shape of said outlet opening in said housing is rectangular.
- 4. An air opening jet apparatus for opening a thin, relatively wide tow of textile filaments and forming the opened tow into a predetermined shape comprising:(a) a housing having an inlet opening for receiving a partially opened tow and an outlet opening through which said tow exits said housing; (b) an air jet formed within the housing adjacent said inlet opening thereof to create a venturi which moves the tow through the air opening jet apparatus and which also further opens the tow; (c) a source of compressed air communicating with said air jet to provide carrier air for moving said tow through said jet apparatus; (d) a forming chamber 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, said air jet being disposed within said housing to cause said tow to be substantially fully opened as it moves therethrough; (e) an accumulating chamber located within said housing downstream of said forming chamber that is constructed and arranged to permit said opened tow to accumulate within the accumulating chamber and be withdrawn from said housing at different flow rates through said housing outlet opening, said accumulating chamber including at least one perforated plate disposed in the path of said tow and said carrier air moving therethrough to cause said tow to engage said perforated plate and to cause at least some of said carrier air to pass through said perforated plate; and (f) a control valve for maintaining the flow of said carrier air at a level that will cause at least said portion of said carrier air to pass through said perforated plate and urge said tow into functional engagement with said perforated plate with sufficient force to retard the movement of the tow through said accumulating chamber and cause said tow to accumulate in said accumulating chamber at a greater density than it has in said forming chamber.
- 5. A method of opening a thin, relatively wide tow of textile filaments and forming the opened tow into a predetermined shape, said method comprising the steps of:(a) creating a jet of carrier air for moving the tow through a housing from an inlet opening to an outlet opening; (b) moving said tow through a forming chamber within said housing having a gradually increasing cross-sectional area in the direction of flow of the tow to partially open the tow; (c) moving the tow into an accumulating chamber downstream of said forming chamber while causing said tow to engage at least one perforated plate positioned in the path of said tow and causing at least a portion of said carrier air to flow outwardly through said perforated plate; and (d) regulating the flow of said carrier air to cause the carrier air to urge the tow into frictional engagement with said perforated plate with sufficient force to retard the movement of the tow through the accumulating chamber and cause the tow to accumulate within said accumulating chamber at a greater density than it has in said forming chamber.
US Referenced Citations (41)
Foreign Referenced Citations (2)
Number |
Date |
Country |
7-49611 |
Mar 1984 |
JP |
WO 8303267 |
Sep 1983 |
WO |