US3633743A
Expired / Lapsed
US
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Process and apparatus for classifying fibres
Assignee: NAT RES DEV
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Filing: 1969-05-05
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Granted: 1972-01-11
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Expires: 1989-05-05
Abstract
Abstract A process and apparatus for classifying fibers for length wherein the fibers are dispersed in a liquid which is tangentially flowed onto a screen, which has a plurality of holes of a size in accordance with the length of fibers desired to be retained on the screen. The screen is in the form of a closed loop which is continuously circulating past the dispersion supply position at a rate sufficient to ensure that only a thin layer of fibers is applied to the screen. After passing the supply position the screen is inverted and a stream of fluid is applied to remove the fibers retained thereon.
Inventors
- 👤 Ronald William Gooding
- 👤 Noel James Parratt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:12
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/36; G01N33/362; B; B03; B03B; B03B7/00; B07; B07B; B07B1/00; B07B1/18; B07B1/22
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
214 words
A method of classifying fibers by length which comprises (a) forming a liquid dispersion of the fiber, (b) feeding the dispersion At a controlled rate and concentration onto a screen which is in the form of a closed loop moving continuously in one direction and having a plurality of holes of a similar size, said size being predetermined in accordance with the minimum length of fibers which is desired to be retained on said screen, said concentration and rate being such that no more than five monolayers of fibers are applied to said screen and that the fibers flow onto the screen with the major component of their velocity in the direction of movement of the screen, (c) removing retained longer fibers from the screen after the bulk of the shorter fibers have passed through the screen by impinging upon said retained fibers a gas jet having a velocity component normal to the plane of the screen sufficient to lift the retained fibers away from the screen and separately collecting said shorter fibers and said longer fibers, and (d) propelling the screen at an angular velocity sufficient to ensure that the major part of the shorter fibers and dispersion medium are passed through the screen by the centrifugal acceleration resulting from this angular velocity.
Claim 2
Independent Claim
214 words
A method of classifying fibers by length which comprises (a) forming a liquid dispersion of the fiber, (b) feeding the dispersion At a controlled rate and concentration onto a screen which is in the form of a closed loop moving continuously in one direction and having a plurality of holes of a similar size, said size being predetermined in accordance with the minimum length of fibers which is desired to be retained on said screen, said concentration and rate being such that no more than five monolayers of fibers are applied to said screen and that the fibers flow onto the screen with the major component of their velocity in the direction of movement of the screen, (c) removing retained longer fibers from the screen after the bulk of the shorter fibers have passed through the screen by impinging upon said retained fibers a gas jet having a velocity component normal to the plane of the screen sufficient to lift the retained fibers away from the screen and separately collecting said shorter fibers and said longer fibers, and (d) propelling the screen at an angular velocity sufficient to ensure that the major part of the shorter fibers and dispersion medium are passed through the screen by the centrifugal acceleration resulting from this angular velocity.
Claim 3
Dependent Claim
63 words
A process according to claim 1 in which the closed loop is a cylindrical screen which rotates at an even rate about a horizontal axis in which the dispersion supply position is situated inside the cylindrical screen above the lower part of the course of the screen, and in which the jet of gas is directed to an upper part of the screen.
Claim 4
Dependent Claim
24 words
A process according to claim 2 and in which the rate of rotation of the screen is between 300 and 1,000 revolutions per minute.
Claim 5
Dependent Claim
31 words
A process according to claim 2 and in which the centrifugal acceleration resulting from the rotation of the cylindrical screen is between 10 and 100 times the acceleration due to gravity.
Claim 6
Dependent Claim
33 words
A process according to claim 2 in which the jet of gas is an air jet delivered through a slit orifice extending in a radial plane across the whole width of the screen.
Claim 7
Dependent Claim
14 words
A process according to claim 5 wherein the slit thickness is about 0.25 inch.
Claim 8
Dependent Claim
61 words
A process according to claim 1 and in which the jet of gas applies to fibers retained on the screen a component of force through the screen sufficient to ensure that the fibers thereby removed from the screen have a resultant path at an angle of at least 25* to the plane of fiber travel immediately before removal from the screen.
Claim 9
Dependent Claim
18 words
A process according to claim 7 and in which the said angle is between 30* and 35* .
Claim 10
Dependent Claim
42 words
A process according to claim 1 and in which a collecting chamber is provided which has a receiving orifice to intercept the removed fibers of a cross section suitable to receive substantially all of the fibers removed by the jet of gas.
Claim 11
Dependent Claim
34 words
A process according to claim 9 and in which the collecting chamber rearward of the orifice is shaped to follow the resultant path of fibers removed from the screen by the jet of gas.
Claim 12
Dependent Claim
30 words
A process according to claim 10 and in which air is continuously withdrawn into the orifice and through the collecting chamber to assist the smooth collection of the said fibers.
Claim 13
Dependent Claim
35 words
A process according to claim 1 and in which the jet of gas is directed onto the screen at right angles to the direction of screen movement with a speed of at least 150 feet/second.
Claim 14
Dependent Claim
26 words
A process according to claim 1 wherein the dispersion is flowed onto the screen with a velocity substantially the same as the velocity of the screen.
Claim 15
Dependent Claim
22 words
A process according to claim 13 wherein the dispersion is supplied through a slit-shaped orifice extending across the width of the screen.
Claim 16
Dependent Claim
30 words
A process according to claim 1 and in which the thickness of the layer of fibers formed on the screen is limited to not more than about 1 1/2 monolayers.
Claim 17
Dependent Claim
31 words
A process according to claim 1 and in which the quantity of liquid applied to the screen to achieve fiber classification is approximately 10 times that amount entrained by the screen.
Claim 18
Dependent Claim
24 words
A process according to claim 16 in which the said quantity of liquid is supplied wholly as the liquid phase of the fiber dispersion.
Claim 19
Dependent Claim
60 words
A process according to claim 16 and in which the said quantity of liquid is applied to the screen partly as the liquid phase of the fiber dispersion and partly at a washing position between the position at which the dispersion is fed onto the screen and the position at which retained fiber is removed by the jet of gas.
Claim 20
Dependent Claim
29 words
A process according to claim 1 and in which a dispersion of the separated short fibers is subsequently recycled through the screen to further improve their classification by length.
Claim 21
Dependent Claim
28 words
A process according to claim 1 and in which a dispersion of separated long fibers is subsequently recycled through the screen to further improve their classification by length.
Claim 22
Dependent Claim
156 words
Apparatus for classifying fibers by length which comprises a screen in the form of a closed loop having a plurality of holes of a similar size which is predetermined in accordance with the minimum length of the fibers desired to be retained on the screen, dispersion supply means mounted above the screen for flowing a dispersion of fibers in a liquid at a controlled rate onto the screen at a dispersion supply position, gas jet supply means for removing retained fibers from the screen, means for collecting fibers passed through the screen, means for collecting fibers removed from the screen by the gas jet, and driving means operably linked with the screen for propelling the screen past the dispersion supply position with an angular velocity sufficient to ensure that the major part of the fibers and dispersion medium to be passed through the screen are so passed by the centrifugal acceleration resulting from this angular velocity.
Claim 23
Dependent Claim
156 words
Apparatus for classifying fibers by length which comprises a screen in the form of a closed loop having a plurality of holes of a similar size which is predetermined in accordance with the minimum length of the fibers desired to be retained on the screen, dispersion supply means mounted above the screen for flowing a dispersion of fibers in a liquid at a controlled rate onto the screen at a dispersion supply position, gas jet supply means for removing retained fibers from the screen, means for collecting fibers passed through the screen, means for collecting fibers removed from the screen by the gas jet, and driving means operably linked with the screen for propelling the screen past the dispersion supply position with an angular velocity sufficient to ensure that the major part of the fibers and dispersion medium to be passed through the screen are so passed by the centrifugal acceleration resulting from this angular velocity.
Claim 24
Dependent Claim
62 words
Apparatus according to claim 21 in which the closed loop is a cylindrical screen which rotates to an even rate about a horizontal axis in which the dispersion supply position is situated inside the cylindrical screen above the lower part of the course of the screen, and in which the jet of gas is directed at an upper part of the screen.
Claim 25
Dependent Claim
23 words
Apparatus according to claim 22 and in which the rate of rotation of the screen is between 300 and 1,000 revolutions per minute.
Claim 26
Dependent Claim
30 words
Apparatus according to claim 22 and in which the centrifugal acceleration resulting from the rotation of the cylindrical screen is between 10 and 100 times the acceleration due to gravity.
Claim 27
Dependent Claim
32 words
Apparatus according to claim 22 in which the jet of gas is an air jet delivered through a slit orifice extending in a radial plane across the whole width of the screen.
Claim 28
Dependent Claim
13 words
Apparatus according to claim 25 wherein the slit thickness is about 0.25 inch.
Claim 29
Dependent Claim
60 words
Apparatus according to claim 22 and in which the jet of gas applies to fibers retained on the screen a component of force through the screen sufficient to ensure that the fibers thereby removed from the screen have a resultant path at an angle of at least 25* to the plane of fiber travel immediately before removal from the screen.
Claim 30
Dependent Claim
16 words
Apparatus according to claim 27 and in which the said angle is between 30* and 35*.
Claim 31
Dependent Claim
41 words
Apparatus according to claim 22 and in which a collecting chamber is provided which has a receiving orifice to intercept the removed fiber of a cross section suitable to receive substantially all of the fibers removed by the jet of gas.
Claim 32
Dependent Claim
33 words
Apparatus according to claim 29 and in which the collecting chamber rearward of the orifice is shaped to follow the resultant path of fibers removed from the screen by the jet of gas.
Claim 33
Dependent Claim
29 words
Apparatus according to claim 29 and in which air is continuously withdrawn into the orifice and through the collecting chamber to assist the smooth collection of the said fibers.
Claim 34
Dependent Claim
34 words
Apparatus according to claim 22 and in which the jet of gas is directed onto the screen at right angles to the direction of screen movement with a speed of at least 150 feet/second.
Claim 35
Dependent Claim
27 words
Apparatus according tO claim 22 and in which the cylindrical screen is internally divided into a first and a second cylindrical section by a circumferential separating wall.
Claim 36
Dependent Claim
207 words
Apparatus for classifying fibers by length, which comprises (a) a screen in the form of a closed loop having a plurality of holes of a similar size which is predetermined in accordance with the minimum length of the fibers to be retained on the screen, said screen being cylindrical and rotatable about a horizontal axis and being internally divided into a first and second section by a circumferential separating wall, (b) first and second dispersion supply means being positioned inside the cylindrical screen sections near the lowest part of the course of the screen, (c) a gas jet supply means for removing retained fibers from the screen, said gas jet being directed at the upper part of each of said cylindrical screen sections, (d) first and second collecting means for collecting fibers passed through said first and second screen sections respectively (e) means for collecting fibers removed from the screen by the gas jet and (f) driving means operably linked with the screen for propelling the screen past the dispersion supply position with an angular velocity sufficient to ensure that the major part of the fibers and dispersion medium to be passed through the screen are so passed by the centrifugal acceleration resulting from this angular velocity.
Claim 37
Dependent Claim
207 words
Apparatus for classifying fibers by length, which comprises (a) a screen in the form of a closed loop having a plurality of holes of a similar size which is predetermined in accordance with the minimum length of the fibers to be retained on the screen, said screen being cylindrical and rotatable about a horizontal axis and being internally divided into a first and second section by a circumferential separating wall, (b) first and second dispersion supply means being positioned inside the cylindrical screen sections near the lowest part of the course of the screen, (c) a gas jet supply means for removing retained fibers from the screen, said gas jet being directed at the upper part of each of said cylindrical screen sections, (d) first and second collecting means for collecting fibers passed through said first and second screen sections respectively (e) means for collecting fibers removed from the screen by the gas jet and (f) driving means operably linked with the screen for propelling the screen past the dispersion supply position with an angular velocity sufficient to ensure that the major part of the fibers and dispersion medium to be passed through the screen are so passed by the centrifugal acceleration resulting from this angular velocity.
Claim 38
Dependent Claim
36 words
Apparatus according to claim 34 and in which there is provided means to feed fibers passing through the first section into the dispersion supply means of the second section to optimize the separation of longer fibers.
Claim 39
Dependent Claim
37 words
Apparatus according to claim 34 and in which there is provided means to feed fibers retained by the first section into the dispersion supply means of the second section to optimize the classification of fibers by length.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |