Patent US4269707A successfully refreshed from Google Patents.
US4269707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method
Assignee: Ecodyne Corp
•
Filing: 1979-11-13
•
Granted: 1981-05-26
•
Expires: 1999-11-13
Abstract
Abstract A filter element having a perforated tubular core and a plurality of layers of strand material wound about the tubular core. The outermost layer has the ability to retain particles smaller than those retained by the innermost layer. The size range of particles retained by the outermost layer is from one to twenty-five microns and the size range of particles retained by the innermost layer is from twenty-five to one hundred microns. According to the method of invention, the filter element is used to purify liquids through the steps of precoating, delivering liquid through the filter, periodically backwashing the filter, and precoating the filter again.
Inventors
- 👤 Donald J. Butterworth
- 👤 Christopher Halbfoster
- 👤 Robert Loudon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:26
CPC Classifications
B; B01; B01D; B01D29/00; B01D29/11; B01D29/111; B01D29/13; B01D29/15; B01D29/21; B01D29/216; B01D29/50; B01D29/52; B01D29/56; B01D29/58; B01D29/62; B01D29/66; B01D37/00; B01D37/02; B01J; B01J47/00; B01J47/12; B01J47/133; B01D2201/00; B01D2201/04; B01D2201/043; B01D2201/0438; B01D2201/18; B01D2201/188
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
91 words
A filter element, precoated with particles in the size range of 60 to 400 mesh, consisting essentially of: a perforated tubular core; an inner layer of strand material wound about said core, said inner layer having a nominal particle retention number between twenty-five and one hundred microns; an outer layer of strand material, wound about said inner layer, said outer layer having a nominal particle retention number between one and twenty-five microns; and a precoat of particles in the size range of 60 to 400 mesh supported on said outer layer.
Claim 2
Dependent Claim
91 words
A filter element, precoated with particles in the size range of 60 to 400 mesh, consisting essentially of: a perforated tubular core; an inner layer of strand material wound about said core, said inner layer having a nominal particle retention number between twenty-five and one hundred microns; an outer layer of strand material, wound about said inner layer, said outer layer having a nominal particle retention number between one and twenty-five microns; and a precoat of particles in the size range of 60 to 400 mesh supported on said outer layer.
Claim 3
Dependent Claim
122 words
A filter element, precoated with particles in the size range of 60 to 400 mesh, comprising: a perforated tubular core; a plurality of layers of strand material, wound about said core, the nominal particle retention number of the innermost layer being greater than the nominal particle retention number of the outermost layer and wherein each of said layers in addition to said innermost layer has a nominal particle retention number less than an adjacent inner layer, wherby the filter element is provided with a plurality of layers having nominal particle retention numbers which gradually decrease from the innermost layer to the outermost layer; and a precoat of particles in the size range of 60 to 400 mesh supported on said outer layer.
Claim 4
Dependent Claim
122 words
A filter element, precoated with particles in the size range of 60 to 400 mesh, comprising: a perforated tubular core; a plurality of layers of strand material, wound about said core, the nominal particle retention number of the innermost layer being greater than the nominal particle retention number of the outermost layer and wherein each of said layers in addition to said innermost layer has a nominal particle retention number less than an adjacent inner layer, wherby the filter element is provided with a plurality of layers having nominal particle retention numbers which gradually decrease from the innermost layer to the outermost layer; and a precoat of particles in the size range of 60 to 400 mesh supported on said outer layer.
Claim 5
Independent Claim
109 words
A method for purifying liquids comprising: precoating a filter having layers of strand material with particles in the size range of about 60 to 400 mesh, said filter having an outermost layer with a nominal particle retention number less than the nominal particle retention number of the innermost layer of said filter with the nominal particle retention numbers gradually decreasing from the innermost layer to the outermost layer; delivering liquid to be filtered through said precoated particles and said filter; periodically backwashing said filter and removing said precoated particles; and precoating said filter with a fresh coating of particles in the size range of about 60 to 400 mesh.
Claim 6
Independent Claim
109 words
A method for purifying liquids comprising: precoating a filter having layers of strand material with particles in the size range of about 60 to 400 mesh, said filter having an outermost layer with a nominal particle retention number less than the nominal particle retention number of the innermost layer of said filter with the nominal particle retention numbers gradually decreasing from the innermost layer to the outermost layer; delivering liquid to be filtered through said precoated particles and said filter; periodically backwashing said filter and removing said precoated particles; and precoating said filter with a fresh coating of particles in the size range of about 60 to 400 mesh.
Claim 7
Dependent Claim
15 words
The method as defined in claim 3 wherein said filter is an annular, wound filter.
Claim 8
Dependent Claim
40 words
The method as defined in claim 3 wherein the nominal particle retention number of the outermost layer is between one and twenty-five microns, and the nominal particle retention number of the innermost layer is between twenty-five and one hundred microns.
References Cited (Backward Citations)
US1751000A
Cited
US2150309A
Cited
US2555201A
Cited
US3065856A
Cited
US3105289A
Cited
US3255889A
Cited
US3279608A
Cited
US3319793A
Cited
US3648846A
Cited
US3779386A
Cited
US3680709A
Cited
US3904798A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-25 | 1984-11-24 | 1985-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-25 | 1988-11-24 | 1989-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-25 | 1992-11-24 | 1993-05-26 | $7700.00 | Window Closed / Lapsed |