US4032688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Seamless tubular nonwoven webs and filters thereof
Assignee: Pall Corp
•
Filing: 1975-05-12
•
Granted: 1977-06-28
•
Expires: 1995-05-12
Abstract
Abstract A process is provided for the continuous production of nonwoven webs in cylindrical or sheet form from thermoplastic fibers, spinning the fibers continuously from a melt onto a rotating mandrel and winding them up on the mandrel to form a generally spirally wound cylinder. Density of the wound cylinder is controlled by controlling the distance between the rotating mandrel and the orifices of the spinning die through which the molten polymeric material is spun. If the spinning of the fibers is continuous, the cylinder can be formed in a continuous length. Control of the spinning rate in relation to the diameter and rate of rotation of the mandrel and the rate of advance of the cylinder on the mandrel controls the thickness of the cylinder. The cylinder can be drawn off the mandrel and used as a cylinder, or either slit lengthwise and opened out, or collapsed onto itself, for use as a sheet. The process is particularly adapted for forming filter elements.
Inventors
- 👤 David B. Pall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:11
CPC Classifications
B; B01; B01D; B01D29/00; B01D29/11; B01D29/111; B01D25/00; B01D25/001; B01D25/22; B01D25/24; B01D29/13; B01D29/15; B01D29/21; B01D29/216; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/20; B01D39/2003; B01D39/2017; D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D04H1/56; D04H1/70; D04H1/76; D04H3/00; D04H3/02; D04H3/07; D04H3/073; B01D2201/00; B01D2201/04; B01D2201/0407; B01D2201/18; B01D2201/188; B01D2239/00; B01D2239/04; B01D2239/0414; B01D2239/0428; B01D2239/0464; B01D2239/06; B01D2239/065; B01D2239/0654; B01D2239/069; B01D2239/0695; B01D2239/08; B01D2239/086; B01D2239/10; B01D2239/12; B01D2239/1233; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1362; Y10T428/249921; Y10T428/249922; Y10T442/00; Y10T442/60; Y10T442/681
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
121 words
A spirally wound tubular filter element comprising a seamless tubular nonwoven web comprising a generally spirally wound flexible layer of unbonded attenuated randomly-oriented heterogeneously intertwined spun fibers substantially all of which are less than 10μ in diameter and in discrete lengths, the layer having an open area of at least 70%, and being held together solely because of the randomly oriented heterogeneous intertwining of the spun fibers, the web being wound spirally on a longitudinally slotted tubular core, the inner end of the interior of the spirally wound flattened cylinder being in fluid flow connection with the slot, and having its opposed sides held apart by a foraminous spacer member for fluid flow within the cylinder to or from the slot.
Claim 2
Dependent Claim
121 words
A spirally wound tubular filter element comprising a seamless tubular nonwoven web comprising a generally spirally wound flexible layer of unbonded attenuated randomly-oriented heterogeneously intertwined spun fibers substantially all of which are less than 10μ in diameter and in discrete lengths, the layer having an open area of at least 70%, and being held together solely because of the randomly oriented heterogeneous intertwining of the spun fibers, the web being wound spirally on a longitudinally slotted tubular core, the inner end of the interior of the spirally wound flattened cylinder being in fluid flow connection with the slot, and having its opposed sides held apart by a foraminous spacer member for fluid flow within the cylinder to or from the slot.
Claim 3
Dependent Claim
29 words
A seamless tubular filter element comprising a nonwoven web according to claim 1 in the form of a cylinder and having end caps at each end of the cylinder.
Claim 4
Dependent Claim
19 words
A seamless tubular nonwoven web according to claim 1 in which the fibers are less than 1μ in diameter.
Claim 5
Dependent Claim
18 words
A seamless tubular nonwoven web according to claim 1 in which the open area is at least 85%.
Claim 6
Dependent Claim
86 words
A seamless tubular nonwoven web comprising a generally spirally wound flexible layer of unbonded attentuated randomly-oriented heterogeneously interwined spun fibers substantially all of which are less than 10μ in diameter and in discrete lengths, the layer having an open area of at least 70%, and being held together solely because of the randomly oriented heterogeneous intertwining of the spun fibers, the generally spirally wound layer being in the form of a cylinder wound on a foraminous tubular core serving as a permanent support for the cylinder.
Claim 7
Dependent Claim
86 words
A seamless tubular nonwoven web comprising a generally spirally wound flexible layer of unbonded attentuated randomly-oriented heterogeneously interwined spun fibers substantially all of which are less than 10μ in diameter and in discrete lengths, the layer having an open area of at least 70%, and being held together solely because of the randomly oriented heterogeneous intertwining of the spun fibers, the generally spirally wound layer being in the form of a cylinder wound on a foraminous tubular core serving as a permanent support for the cylinder.
Claim 8
Dependent Claim
24 words
A seamless tubular filter element comprising a nonwoven web and core according to claim 5, having end caps at each end of the cylinder.
Claim 9
Dependent Claim
19 words
A seamless tubular nonwoven web according to claim 5 in which the fibers are less than 1μ in diameter.
Claim 10
Dependent Claim
18 words
A seamless tubular nonwoven web according to claim 5 in which the open area is at least 85%.
References Cited (Backward Citations)
US3065856A
Cited
US3148101A
Cited
US3334752A
Cited
US3455460A
Cited
US3676242A
Cited
US3691004A
Cited
US3904798A
Cited
US3949130A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |