US3922190A
Expired / Lapsed
US
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Vacuum drainage device having a plurality of stepped blades
Assignee: Inotech Process Ltd
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Filing: 1974-09-10
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Granted: 1975-11-25
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Expires: 1994-09-10
Abstract
Abstract A vacuum drainage device for the forming fabric on a Fourdrinier machine which includes a transversely extending vacuum box and a plurality of stationary stepped blades having a flat support surface and a recessed trailing surface which normally does not support the forming fabric. Both water drainage and wire screen motion is effected by a series of these stepped blades. A hydrodynamic nip is formed between the forming fabric and the trailing surface when vacuum is applied by the vacuum box, thereby effectively limiting the drainage suction to the distance between the nip and the leading edge of a succeeding blade.
Inventors
- 👤 Wavell Frederick Cowan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:35
CPC Classifications
D; D21; D21F; D21F1/00; D21F1/48; D21F1/52; D21F1/523
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
224 words
A DRAINAGE DEVICE FOR DRAINING A MOVING FORMING FABRIC INCLUDING, IN COMBINATION, FIRST LEADING SURFACE ADAPTED TO SUPPORT THE FROMING FABRIC DISPOSED TRANSVERSE OF THE DIRECTION TOF TRAVEL THEREOF, A TRAILING SURFACE DISPOSED TRANSVERSE OF THE DIRECTION OF TRAVEL OF SAID FORMING FABRIC DOWNSTREAM FROM SAID FIRST LEADING SUPPORT SURFACE, AN INTERMEDIATE SURFACE PROVIDED BETWEEN THE FIRST LEADING SUPPORT SURFACE AND THE TRAILING SURFACE DIVERGING FROM THE PLANE OF SAID LEADNG SUPPORT SURFACE IN THE DIRECTION OF SAID TRAILING SURFACE AT AN ANGLE EXCEEDING 5*, A SECOND SUPPORT SURFACE ADAPTED TO SUPPORT THE FORMING FABRIC DISPOSED TRANSVERSE OF THE DIRECTION OF TRAVEL THEREOF AND SPACED DOWNSTREAM OF SAID TRAILING SURFACE AND FORMING A GAP THEREBETWEEN, MEANS FOR APPLYING SUCTION IN SAID GAP, SAID TRAILING SURFACE HAVING A DEPTH BELOW THE FIRST AND SECOND SUPPORT SURFACES AND A LENGTH WHEREBY THE MOVING FABRIC IS NOT NORMALLY SUPPORTING BY SAID TRAILING SURFACE, THE DISTANCE BETWEEN THE FORMING FABRIC AND THE TRAILING SURFACE NOT EXCEEDING A DISTANCE NECESSARY FOR FORMATION AND MAINTENANCE OF A HYDRODYNAMIC NIP THEREBETWEEN UPON THE APPLICATION OF SUCTIN BY SAID MEANS FOR APPLYING SUCTION WHICH WILL EFFECTIVELY PREVENT LIQUID FROM FLOWING BETWEEN THE FORMING FABRIC AND THE TRAILING SURFACE THEREBY EFFECTIVELY LIMITING THE DRAINAGE SUCTION TO THE DISTANCE BETWEEN SAID NIP AND SAID SECOND SUPPORT SURFACE UPON WHICH SAID FORMING FABRIC IS SUPPORTED.
Claim 2
Dependent Claim
224 words
A DRAINAGE DEVICE FOR DRAINING A MOVING FORMING FABRIC INCLUDING, IN COMBINATION, FIRST LEADING SURFACE ADAPTED TO SUPPORT THE FROMING FABRIC DISPOSED TRANSVERSE OF THE DIRECTION TOF TRAVEL THEREOF, A TRAILING SURFACE DISPOSED TRANSVERSE OF THE DIRECTION OF TRAVEL OF SAID FORMING FABRIC DOWNSTREAM FROM SAID FIRST LEADING SUPPORT SURFACE, AN INTERMEDIATE SURFACE PROVIDED BETWEEN THE FIRST LEADING SUPPORT SURFACE AND THE TRAILING SURFACE DIVERGING FROM THE PLANE OF SAID LEADNG SUPPORT SURFACE IN THE DIRECTION OF SAID TRAILING SURFACE AT AN ANGLE EXCEEDING 5*, A SECOND SUPPORT SURFACE ADAPTED TO SUPPORT THE FORMING FABRIC DISPOSED TRANSVERSE OF THE DIRECTION OF TRAVEL THEREOF AND SPACED DOWNSTREAM OF SAID TRAILING SURFACE AND FORMING A GAP THEREBETWEEN, MEANS FOR APPLYING SUCTION IN SAID GAP, SAID TRAILING SURFACE HAVING A DEPTH BELOW THE FIRST AND SECOND SUPPORT SURFACES AND A LENGTH WHEREBY THE MOVING FABRIC IS NOT NORMALLY SUPPORTING BY SAID TRAILING SURFACE, THE DISTANCE BETWEEN THE FORMING FABRIC AND THE TRAILING SURFACE NOT EXCEEDING A DISTANCE NECESSARY FOR FORMATION AND MAINTENANCE OF A HYDRODYNAMIC NIP THEREBETWEEN UPON THE APPLICATION OF SUCTIN BY SAID MEANS FOR APPLYING SUCTION WHICH WILL EFFECTIVELY PREVENT LIQUID FROM FLOWING BETWEEN THE FORMING FABRIC AND THE TRAILING SURFACE THEREBY EFFECTIVELY LIMITING THE DRAINAGE SUCTION TO THE DISTANCE BETWEEN SAID NIP AND SAID SECOND SUPPORT SURFACE UPON WHICH SAID FORMING FABRIC IS SUPPORTED.
Claim 3
Dependent Claim
178 words
A drainage device for draining a moving forming fabric comprising a vacuum box extending transversely of the direction of travel of the forming fabric, a plurality of drainage blades extending longitudinally on the vacuum box and spaced apart forming a gap therebetween, each blade including a leading support surface for supporting the forming fabric, an intermediate surface diverging from the plane of the support surface at an angle exceeding 5*, and a recessed trailing surface having a depth such that it does not support a span of the moving forming fabric and having a length such that the lowest point of the forming fabric between the leading support surfaces of succeeding blades and the trailing surface is spaced a distance necessary to prevent water from flowing between the forming fabric and the recessed trailing surface such that a hydrodynamic nip is formed between the forming fabric and the trailing surface when vacuum is applied by the vacuum box, thereby effectively limiting the drainage suction to the distance between the nip and a leading edge of a succeeding blade.
Claim 4
Dependent Claim
178 words
A drainage device for draining a moving forming fabric comprising a vacuum box extending transversely of the direction of travel of the forming fabric, a plurality of drainage blades extending longitudinally on the vacuum box and spaced apart forming a gap therebetween, each blade including a leading support surface for supporting the forming fabric, an intermediate surface diverging from the plane of the support surface at an angle exceeding 5*, and a recessed trailing surface having a depth such that it does not support a span of the moving forming fabric and having a length such that the lowest point of the forming fabric between the leading support surfaces of succeeding blades and the trailing surface is spaced a distance necessary to prevent water from flowing between the forming fabric and the recessed trailing surface such that a hydrodynamic nip is formed between the forming fabric and the trailing surface when vacuum is applied by the vacuum box, thereby effectively limiting the drainage suction to the distance between the nip and a leading edge of a succeeding blade.
Claim 5
Dependent Claim
19 words
A drainage device as defined in claim 1, wherein the angle of divergence of the intermediate surface is 90*.
Claim 6
Dependent Claim
63 words
A drainage device as defined in claim 1, wherein the span is between 1.95 inches and 5.00 inches, the gap distance between successive blades is in the range of 0.25 inch to 2.00 inches and the depth of the recess is between 0.005 inch and 0.120 inch with the length of said trailing recess surface being between about 1 inch to 4 inches.
Claim 7
Dependent Claim
48 words
A drainage device as defined in claim 3, wherein there are nine blades provided in a vacuum box and the span between blades is 2.25 inches with a recess length of 1.69 inches and a gap distance of 0.56 inch, the depth of the recess being 0.030 inches.
Claim 8
Dependent Claim
51 words
A drainage device as defined in claim 3, wherein there are seven blades provided in a vacuum box and the span between blades is 3.17 inches with a recess length of 2.54 inches and a gap distance of 0.63 inches, the depth of the recess being 0.045 inches and 0.060 inches.
Claim 9
Dependent Claim
48 words
A drainage device as defined in claim 3, wherein there are five blades provided in a vacuum box and the span between blades is 5.00 inches with a recess length of 4.00 inches and a gap distance of 1.00 inch, the depth of the recess being 0.045 inches.
Claim 10
Dependent Claim
24 words
A drainage device as defined in claim 3, wherein the depth of the recess is within a range of 0.030 inches and 0.090 inches.
Claim 11
Dependent Claim
21 words
A drainage device as defined in claim 7, wherein the depth of the recess is between 0.045 inches and 0.060 inches.
Claim 12
Dependent Claim
26 words
A drainage device in accordance with claim 9, in which said first leading support surface, said intermediate surface and said trailing surface provide a first blade.
Claim 13
Dependent Claim
45 words
A drainage device in accordance with claim 10, in which a plurality of blades substantially identical to said first blade are provided, and said second support surface is a portion of a second blade of said plurality which trails said first blade in said device.
Claim 14
Dependent Claim
24 words
A drainage device in accordance with claim 9, in which said first leading surface and said trailing surface are substantially horizontal flat parallel planes.
Claim 15
Dependent Claim
85 words
A drainage device as defined in claim 9, wherein the distance between the first leading surface and a second support surface is between 1.95 inches and 5.00 inches, the distance of the gap is in the range of 0.25 inch to 2.00 inches, the length of the trailing surface is selected within a range between 1.00 inch and 4.00 inches, and the depth of the trailing surface below the first and second support surfaces is in a range of between 0.005 inch and 0.120 inch.
Claim 16
Dependent Claim
24 words
A drainage device as defined in claim 13, wherein the depth of the recess is within a range between 0.030 inch and 0.090 inch.
Claim 17
Dependent Claim
21 words
A drainage device as defined in claim 14, wherein the depth of the recess is between 0.045 inch and 0.060 inch.
Claim 18
Dependent Claim
48 words
A drainage device as defined in claim 11, wherein there are nine blades provided in a vacuum box and the span between blades is 2.25 inches with a recess length of 1.69 inches and a gap distance of 0.56 inch, the depth of the recess being 0.030 inches.
Claim 19
Dependent Claim
51 words
A drainage device as defined in claim 11, wherein there are seven blades provided in a vacuum box and the span between blades is 3.17 inches with a recess length of 2.54 inches and a gap distance of 0.63 inches, the depth of the recess being 0.045 inches and 0.060 inches.
Claim 20
Dependent Claim
48 words
A drainage device as defined in claim 11, wherein there are five blades provided in a vacuum box and the span between blades is 5.00 inches with a recess length of 4.00 inches and a gap distance of 1.00 inch, the depth of the recess being 0.045 inches.
Claim 21
Dependent Claim
184 words
In a drainage device for draining a moving forming fabric which is passed thereover under the influence of suction and having spaced apart forming fabric support surfaces, a blade having a leading surface comprising a forming fabric support surface, said bladE having a trailing surface and an intermediate surface between the leading support surface and the trailing surface diverging from the plane of said leading support surface in the direction of said trailing surface at an angle exceeding 5*, said trailing surface having a depth relative to the leading surface and a length whereby the forming fabric is not normally supported by the trailing surface and so that upon the application of suction between said trailing surface and a succeeding forming fabric support surface on the drainage device, liquid drained from said forming fabric will provide a hydrodynamic nip between said forming fabric and said trailing surface, which will effectively prevent liquid from flowing between the forming fabric and the trailing surface thereby effectively limiting the drainage suction to the distance between said hydrodynamic nip and the succeeding support surface of the drainage device.
Claim 22
Dependent Claim
184 words
In a drainage device for draining a moving forming fabric which is passed thereover under the influence of suction and having spaced apart forming fabric support surfaces, a blade having a leading surface comprising a forming fabric support surface, said bladE having a trailing surface and an intermediate surface between the leading support surface and the trailing surface diverging from the plane of said leading support surface in the direction of said trailing surface at an angle exceeding 5*, said trailing surface having a depth relative to the leading surface and a length whereby the forming fabric is not normally supported by the trailing surface and so that upon the application of suction between said trailing surface and a succeeding forming fabric support surface on the drainage device, liquid drained from said forming fabric will provide a hydrodynamic nip between said forming fabric and said trailing surface, which will effectively prevent liquid from flowing between the forming fabric and the trailing surface thereby effectively limiting the drainage suction to the distance between said hydrodynamic nip and the succeeding support surface of the drainage device.
Claim 23
Dependent Claim
43 words
A blade as defined in claim 19, wherein the depth of the trailing surface relative to the leading surface is in a range between 0.005 inch and 0.120 inch and the length of the trailing surface is between 1.00 inch and 4.00 inches.
Claim 24
Dependent Claim
26 words
A blade as defined in claim 20, wherein the angle of divergence from the plane of the leading support surface, of the intermediate surface, is 90*.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |