Claims
- 1. In a machine for forming random fiber webs, having a first rotary foraminate condenser, means for delivering airborne fibers onto said first condenser to form a fiber mat on said first condenser, a rotary lickerin mounted beneath said first condenser, means for doffing the mat from said first condenser and feeding the mat to the lickerin so that the lickerin in its rotation combs fibers from the mat, a cylindrical saber mounted in spaced, confronting relation to said lickerin to assist in doffing fibers therefrom, and an endless foraminate condenser whose upper reach at least travels in a horizontal plane beneath said lickerin, the improvement comprising
- a pair of tapered, vertically disposed ducts positioned one above the other with their narrow ends opening on the space between said lickerin and said saber, said space forming a venturi section between said ducts, and the lower of said pair of ducts extending from said venturi section to and above the upper reach of the last-named condenser,
- pneumatic means for creating a high velocity air stream in said lower duct to doff fibers from said lickerin and to convey the doffed fibers in a vertically downward direction onto the upper reach of said last-named condenser,
- said pneumatic means including means for recirculating said air stream downwardly through the upper of said ducts and tangentially past said lickerin and into the upper end of said lower duct, after the stream has passed through the upper reach of said last-named condenser, and
- means for controlling the air flow in said ducts to minimize turbulence in said lower duct, including means eccentrically mounting said saber for rotational adjustment selectively to vary the distance between said saber and said lickerin, and
- means for controlling the supply of air to said ducts.
- 2. A machine as claimed in claim 1, wherein said lower duct is rectangular in configuration and has a gradually increasing cross sectional area downwardly from said lickerin to said last-named condenser to provide an expansion chamber at least one side of which is mounted for pivotal adjustment to control the width of the discharge end of the lower duct.
- 3. A machine as claimed in claim 2, wherein each pair of opposed walls of said lower duct diverge downwardly to said last-named condenser and form said expansion chamber.
- 4. A machine as claimed in claim 1 wherein said recirculating means includes
- an expansion chamber,
- a slotted air distribution tube connected to said expansion chamber, and
- a distribution chamber in which said tube is mounted and into which air flows through the slot in said tube, said upper duct communicating at its upper end with said distribution chamber.
- 5. A machine as claimed in claim 4, wherein a perforate diffuser is mounted in said distribution chamber adjacent the upper end of said upper duct.
- 6. A machine as claimed in claim 5, wherein said distribution chamber is of large cross-sectional area adjacent said diffuser and is of venturi formation below said large cross-sectional area and opposite said lickerin.
- 7. A machine as claimed in claim 1, wherein
- a doffing bar is mounted in operative relation to said lickerin,
- said air flow controlling means included a plurality of air inlet slots provided in one wall of said lower duct adjacent the doffing bar, and
- means is provided for adjustably controlling the area of opening of said inlet slots into said lower duct.
- 8. A machine as claimed in claim 1, wherein
- said lower duct has one wall thereof mounted adjacent its upper end for pivotal adjustment about an axis parallel to the axis of rotation of said lickerin.
Parent Case Info
This application is a continuation-in-part of my application Ser. No. 337,019, filed Mar. 1, 1973, now abandoned.
The present invention relates to machines for forming random fiber webs, and more particularly to such machines in which a fiber mat is fed to a rotating lickerin, which combs individual fibers from the mat; and the fibers are doffed from the lickerin by centrifugal force and by an air stream flowing tangentially past the lickerin, and the doffed fibers are carried in suspension in the air stream to a moving foraminate condenser, on which the fibers are deposited in random fashion to form the random or non-woven fiber web. The webs are suitable for producing high quality non-woven fabrics by known chemical or mechanical bonding treatments.
Because the duct between the lickerin and the condenser is generally horizontal, prior machines of the type described are generally horizontal in their major direction, and occupy considerable floor space. If a fiber feeder is attached to the web forming machine, as is generally the case nowadays in practice, the amount of floor space occupied by the combination feeder-webber is quite considerable; and floor space is expensive.
Non-woven fabrics are produced from web structures by chemically bonding or by mechanically interlocking the fibers together. The dry formed structures may be chemically bonded by known means such as the application of adhesives by spray or by saturation, also bonding may be accomplished by the use of fibers which have a low melting point and form a bond to nonadhesive fibers by heat and pressure. Mechanical bonding may be carried out by needling, or stitch bonding may be used; also apertured or print bonding may be used to provide strength and durability. The quality of any non-woven fabric produced by these finishing methods depends upon the quality and uniformity of the web structure which is to be treated or finished.
Webs suitable for producing random non-woven web structure have been prepared by aerodynamic formation apparatus such as manufactured by Rando Machine Corporation and known as "Rando-Webbers" and disclosed in U.S. Pat. Nos. 2,451,915, 2,700,188, 2,890,497, 3,535,187, 3,512,218 and 3,768,119.
Non-woven web structures formed by aerodynamic means are normally produced by opening and blending various fibers to separate the fibrous mass into individual fibers. The opened fibers are formed into a uniform feed mat. The opening and the formation of the feed mat are extremely important to the final web structure since any non-uniformity or poor opening will cause unwanted irregularities in the final product.
The uniform feed mat is fed via a toothed or clothed feed roll to a similarly covered lickerin, and a stream of air is caused to move over the surface of this lickerin by either a positive or negative air pressure. The lickerin is rotated at high speed to feed or comb the fibers from the feed mat into the air stream, the objective being to feed individual fibers rather than clumps or group of fibers. The fibers are carried in the machines of the present invention by the high velocity air stream as a dilute dispersion downwards through a vertical conduit to a condensing screen surface moving at right angles to the flow in the vertical path, and are deposited over a relatively large surface area to form a random structure on the moving screen.
The primary object of the present invention is to provide an aerodynamic process and apparatus suitable for high speed production of uniform webs of excellent quality from uniform feed mats made of fibrous materials.
Another object of the present invention is to provide a web forming machine which will be more compact than prior such machines, and which will occupy a minimum of floor space.
Another object of the invention is to provide a combination fiber feeder and webber, which together will be much more compact than prior such combinations.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.
US Referenced Citations (9)
Foreign Referenced Citations (3)
| Number |
Date |
Country |
| 1,172,561 |
Oct 1958 |
FR |
| 688,216 |
Feb 1940 |
DT |
| 893,686 |
Apr 1962 |
UK |
Continuation in Parts (1)
|
Number |
Date |
Country |
| Parent |
337019 |
Mar 1973 |
|
Patent Grant
3972092
