US3727270A - Vacuum drafting of fibrous strands - Google Patents

Vacuum drafting of fibrous strands Download PDF

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Publication number
US3727270A
US3727270A US00164255A US3727270DA US3727270A US 3727270 A US3727270 A US 3727270A US 00164255 A US00164255 A US 00164255A US 3727270D A US3727270D A US 3727270DA US 3727270 A US3727270 A US 3727270A
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Prior art keywords
stream
fibers
strand
vacuum
tube
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Expired - Lifetime
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US00164255A
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English (en)
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P Marshall
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Fiber Technology Corp
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Kendall Co
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    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
    • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged

Definitions

  • This invention relates to a two-stage process for the pneumatic drafting of individual textile-length fibers from a strand comprising a multiplicity of such fibers, and to a process for depositing the resulting air-borne fibers in the form of a fleece or web. More particularly it relates to a process wherein fibers are drawn from a tip-draftable strand by vacuum into an open-end tube, accelerated in an attenuated stream along the length of said tube, and are subjected to a second stage of acceleration and attenuation by an air stream of high velocity upon emerging from the exit end of said tube.
  • a tip-draftable strand of textile-length fibers can be transformed into' a fibrous stream by a two-stage process wherein the primary operating force serving to separate fibers from the strand is applied by exposing the end of the strand to a fiber-drafting vacuum developed at the entrance end of an open-end vacuum tube.
  • the air in the vacuum tube is preferably at or near sonic velocity.
  • the stream of fibers thus formed is then further accelerated to a higher velocity, in a second step, by means of a second high velocity air stream after leaving the exit end of the tube.
  • the fibers in the strand are more thoroughly separated and individualized than by the process set forth in Ser. No. 159,229 with a consequently greater uniformity of fiber dispersion when they are decelerated and diffused in a plenum chamber, and improved web uniformity when the diffused fiber cloud is collected. in web form.
  • FIG. 1 is a cross-sectional view of an aspirator tube suitable for carrying out the process of the invention.
  • FIG. 2 is an enlarged cross-sectional view, partly broken away, of the entrance and exit portions of the strand-guide tube of the aspirator of FIG. 1.
  • FIG. 3 is a set of curves showing the variation of static vacuum measured in the entrance end of the tube, in inches of mercury, with air pressure applied at the jet section of the aspirator, in pound per square inch gauge.
  • FIG. 4 is a cross-sectional side view of a plenum chamber suitable for the deceleration and diffusion of an air-borne stream of fibers.
  • FIG. 5 is a front elevation of the plenum chamber of FIG. 4.
  • serial steps involved in creating an accelerated stream of air-borne fibers according to this invention comprise:
  • a tip-draftable strand in this application is taken to mean a sliver or top of textile-length fibers, commonly 1 inch to 6 or 8 inches in length, assembled together into a coil or strand wherein the fibers are generally parallelized, and wherein the internal inter-fiber frictional forces of twist, crimp, or finish are insufficient to completely restrain the fibers when the leading end of said strand is subjected to a high-velocity air stream.
  • the impingement of such a high-velocity air stream on the end of said strand by aerodynamic drafting, draws off individual fibers or small groups of parallel fibers rather than tangled segments of the strand.
  • a strand 13 comprising a multiplicity of substantially parallelized fibers, restrained at A by passing through the revolving feed rolls 17,17, is exposed at point B to the action of a strong vacuum, preferably 15 to 25 inches of mercury, established at the entrance end 18 of the vacuum tube or nozzle 10.
  • the action of the vacuum at point B is one of strand at,-
  • the fibrous stream is thus free to be further accelerated as at C in the guide tube 16, and upon emerging from this guide tube is again subjected as at D to a high velocity air stream established in the divergent section 25 of the tube.
  • vacuum tubes suitable for the practice of this invention may be the same as the jet nozzles described in my copending application Ser. No. 159,229, the differences in process lying in the parameters of air pressure.
  • Ser. No. 159,229 a strand comprising a multiplicity of fibers is fed through the inlet tube of a jet nozzle, remaining substantially constant in cross-sectional population until it is tip-drafted at or near the exit end of the guide tube.
  • tip drafting and strand attenuation occur in two stages, the first stage being exterior to the entrance end of the guide tube which is under vacuum.
  • the vacuum tube comprises a cylindrical chamber 15, with wall section 12, capped at one end by an inlet cap 20 containing a tapered inlet 18 for the introduction of a tipdrafted stream of fibers, through guide tube 16 which is attached to the cap 20.
  • the other end of the chamber is capped by an exit cap 24, which restrains the straight exit section 22 and the convergent-divergent nozzle section 23 of the device.
  • sections 22 and 23 are separated pieces, fitting in sliding relationship in the chamber 15. In operation they are held against lateral displacement toward the inlet tube by the air pressure in the chamber 15.
  • Air under pressure is fed to the chamber 15 by means of the air connection 14.
  • the distance to which the guide tube 16 projects past the nozzle portion 23 of the device is adjustable by means of the threaded cap 20.
  • the air, under pressure is so adjusted as to create a propagated vacuum which extends back through the guide tube 16 and establish a substantial vacuum at the entrance 18 thereof.
  • the air stream, converted to a convergent form in the convergent section 21 of the nozzle diverges in section 25 and further accelerates and attenuates the fibrous stream. In this manner a doubly-attenuated fibrous stream is expelled through the nozzle orifice 26 in the cap 24.
  • the dimensions and relative proportions of a suitable tube will of course vary with the denier of the tipdraftable strand used as a source of fibers, and with the output poundage at which it is desired to operate the process.
  • the device of FIG. 1 may, for example, be formed from a 10 inch length of brass pipe 2 inches I.D., with a similar piece of pipe 14 silver-soldered thereto.
  • Type B with guide tube interior diameter of 0.75 inch, is suitable for processing heavy fibrous strands of up to 500,000 denier.
  • suitable vacuum tubes or aspirators are exemplary and not restrictive. In general, the following considerations may be used as basic guides for the selection of an aspirator capable of developing a substantial vacuum at its entrance or feed end, suitable for the double-drafting ofa textile strand.
  • Either low pressure or high pressure tubes may be used, the former requiring proportionately larger quantities of air to power a given size of tube.
  • a tube designed to produce a maximum vacuum at a given air pressure will produce a lower vacuum at either higher or lower air pressure, as seen by the shape of the curves of FIG. 3.
  • the energy required to power a given tube at a given vacuum will be determined primarily by the cross-sectional area of the tube. This area in turn will depend primarily on the size of the strand or strands to be dispersed.
  • the vacuum which drafts the strand into the tube is best measured in a static condition, since Pitot tube measurements of dynamic or operating vacuum are not reliable when the air velocity is above about 0.7 Mach number. For this reason, the preferred vacuum of 15 to 25 inches of mercury is measured by completely blocking the entrance area of the tube with a manometer and adjusting the air pressure accordingly.
  • FIG. 4 there is shown a suitable plenum chamber with the side panel removed.
  • a tip draftable strand of fibers 1 3, metered by the nip rolls l7, 17, is vacuum drafted into the aspirator tube in a fine stream of fibers, accelerated and further attenuated by the impact of a second high velocity air stream in the divergent section of the tube, as set forth above.
  • the resulting double-drafted. high speed fibrous stream as it issues from the aspirator tube 10 diffuses a stream of individually separated fibers into the upper chamber 30.
  • the web is to be subjected to subsequent treatment such as lamination with another substrate
  • a layer of permeable supportive material such as gauze, cellulose tissue, porous nonwoven fabric, or the like.
  • Such expedients are well-known in the art, and are not shown.
  • manageable velocity means a stream velocity at which the fibers can be deposited continuously onto a moving porous belt with substantial absence of fiber clumping or deflection of the stream.
  • the purpose of the plenum chamber or diffusor therefore, is to spread the high speed jet stream over a large cross section, so that the kinetic energy of the stream is transferred to pressure, by diffusion. This pressure forces the air through the porous conveyor, which filters out the fibers in web or fleece form.
  • a Convenient range of exit velocity that is, the air velocity at which the decelerated fibrous stream impinges on the porous conveyor belt has been found to be 3 to 30 feet per second.
  • EXAMPLE 1 A 191.317 denier rayon top, consisting of 34,785 fibers in cross-section, each fiber being 5.5 denier and approximately 6 inches long, was prepared from a continuous filament rayon tow cut by a Pacific Converter and then pin-drafted. It was passed between restraining rolls to a jet of Type B in the table above operating at an air pressure of PSIG at a rate of21.6 feet per minute or 18.6 pounds per hour. The distance between the rolls 27, 17 and the entrance end of the aspirator tube device was approximately 7 inches.
  • the high velocity air stream of fibers was fed directly from the exit section of the tube 10 to the plenum chamber of FIG. 4, whence it was collected on the conveyor screen as a light, uniform web 40 inches wide, of 6-inch fibers weighing 65.3 grams per square yard, at a rate of 5.78 feet per minute.
  • the stream of fibers was exhausted into the plenum chamber of Example 1, forming a web 40 inches wide, weighing 18 grams per square yard, at a rate of 45.56 feet per minute.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Preliminary Treatment Of Fibers (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Nonwoven Fabrics (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
US00164255A 1971-07-20 1971-07-20 Vacuum drafting of fibrous strands Expired - Lifetime US3727270A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US16425571A 1971-07-20 1971-07-20

Publications (1)

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US3727270A true US3727270A (en) 1973-04-17

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US00164255A Expired - Lifetime US3727270A (en) 1971-07-20 1971-07-20 Vacuum drafting of fibrous strands

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US (1) US3727270A (xx)
JP (1) JPS575899B1 (xx)
AR (1) AR204689A1 (xx)
AU (1) AU457572B2 (xx)
BE (1) BE786417A (xx)
BR (1) BR7204317D0 (xx)
CA (1) CA951483A (xx)
CH (1) CH554440A (xx)
DE (1) DE2235270C3 (xx)
DK (1) DK138341B (xx)
ES (1) ES404445A1 (xx)
FI (1) FI52599C (xx)
FR (1) FR2146232B1 (xx)
GB (1) GB1340300A (xx)
IT (1) IT968280B (xx)
NL (1) NL171179C (xx)
NO (1) NO134018C (xx)
SE (1) SE394296B (xx)
ZA (1) ZA724247B (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969561A (en) * 1974-09-17 1976-07-13 The Kendall Company Biaxially oriented nonwoven fabrics and method of making same
US4054628A (en) * 1974-09-17 1977-10-18 The Kendall Company Method of making biaxially oriented nonwoven fabrics
US4169003A (en) * 1976-12-10 1979-09-25 The Kendall Company Flat-pack battery separator
US4369549A (en) * 1980-05-16 1983-01-25 Badische Corporation Blending method using a roving disintegrator-dispenser
US4383349A (en) * 1980-08-04 1983-05-17 The Kendall Company Opening bonded glass fiber bundles
US4535512A (en) * 1983-09-26 1985-08-20 Platt Saco Lowell Corporation Method and means for providing assemblages of opened fibers for intimate blends
US5983457A (en) * 1998-04-29 1999-11-16 Toney; Jerry L. Inlet and outlet plenum apparatus for uniform delivery of fiber to a pad former
US20030033699A1 (en) * 1999-10-12 2003-02-20 Frank Ficker Process and apparatus for the stretching textile fibers

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109518310B (zh) * 2019-01-15 2024-04-02 天津工业大学 一种异纤分拣机剔除系统喷管板

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523300A (en) * 1966-08-18 1970-08-04 Toray Industries Spinning method and apparatus for manufacturing yarn from textile fibers
US3604194A (en) * 1968-01-30 1971-09-14 Toray Industries Fiber supply method and apparatus in an open-end spinning system utilizing airflow and centrifugal force

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD82801A (xx) *
US3124844A (en) * 1960-06-10 1964-03-17 Means to process fibers in a tow or sheet-like material
US3403425A (en) * 1966-06-16 1968-10-01 Tajima Eiichi Method of manufacturing webs
US3341394A (en) * 1966-12-21 1967-09-12 Du Pont Sheets of randomly distributed continuous filaments

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523300A (en) * 1966-08-18 1970-08-04 Toray Industries Spinning method and apparatus for manufacturing yarn from textile fibers
US3604194A (en) * 1968-01-30 1971-09-14 Toray Industries Fiber supply method and apparatus in an open-end spinning system utilizing airflow and centrifugal force

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969561A (en) * 1974-09-17 1976-07-13 The Kendall Company Biaxially oriented nonwoven fabrics and method of making same
US4054628A (en) * 1974-09-17 1977-10-18 The Kendall Company Method of making biaxially oriented nonwoven fabrics
US4169003A (en) * 1976-12-10 1979-09-25 The Kendall Company Flat-pack battery separator
US4369549A (en) * 1980-05-16 1983-01-25 Badische Corporation Blending method using a roving disintegrator-dispenser
US4383349A (en) * 1980-08-04 1983-05-17 The Kendall Company Opening bonded glass fiber bundles
US4535512A (en) * 1983-09-26 1985-08-20 Platt Saco Lowell Corporation Method and means for providing assemblages of opened fibers for intimate blends
US5983457A (en) * 1998-04-29 1999-11-16 Toney; Jerry L. Inlet and outlet plenum apparatus for uniform delivery of fiber to a pad former
US20030033699A1 (en) * 1999-10-12 2003-02-20 Frank Ficker Process and apparatus for the stretching textile fibers

Also Published As

Publication number Publication date
SE394296B (sv) 1977-06-20
BR7204317D0 (pt) 1973-06-12
DK138341C (xx) 1979-01-29
IT968280B (it) 1974-03-20
NO134018B (xx) 1976-04-26
NL7209799A (xx) 1973-01-23
AR204689A1 (es) 1976-02-27
JPS575899B1 (xx) 1982-02-02
GB1340300A (en) 1973-12-12
NL171179C (nl) 1983-02-16
ZA724247B (en) 1973-03-28
FI52599C (fi) 1977-10-10
AU457572B2 (en) 1975-01-30
BE786417A (fr) 1972-11-16
DE2235270C3 (de) 1981-10-15
ES404445A1 (es) 1975-06-16
CA951483A (en) 1974-07-23
FR2146232A1 (xx) 1973-03-02
NO134018C (xx) 1976-08-04
FR2146232B1 (xx) 1976-01-16
DE2235270B2 (de) 1981-01-29
FI52599B (xx) 1977-06-30
AU4377072A (en) 1974-02-21
NL171179B (nl) 1982-09-16
DE2235270A1 (de) 1973-02-08
CH554440A (de) 1974-09-30
DK138341B (da) 1978-08-14

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Owner name: FIBER TECHNOLOGY CORPORATION,STATELESS

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Effective date: 19871203

Owner name: FIBER TECHNOLOGY CORPORATION

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