US3556304A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plastic filter candle
Assignee: Porous Plastics Ltd
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Filing: 1968-09-18
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Granted: 1971-01-19
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Expires: 1988-09-18
Abstract
Abstract A filter which consists of a foraminous tubular spacer made of two layers of integrally extruded filaments with one end closed with a welded-on cap and the other end provided with a flange and outlet aperture. The interior of the spacer is occupied by a reinforcing tubular core of sintered coarse-grained polymer and a tubular porous polymer filter septum is releasably secured over the spacer enabling it to be removed and replaced by a fresh filter septum when necessary.
Inventors
- 👤 Ronald Thomas Collard
- 👤 Phillip Brian Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:28
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1638; B01D39/1653; B01D39/1661; B01D29/00; B01D29/11; B01D29/13; B01D29/15; B01D29/50; B01D29/52; B01D37/00; B01D37/02; B01D2201/00; B01D2201/04; B01D2201/043; B01D2201/0446; B01D2201/18; B01D2201/182
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
75 words
A filter including a tubular filter septum of porous synthetic polymer material surrounding a reinforcing tubular core comprising coarse grains of synthetic polymer material sintered together, a foraminous tubular spacer formed by a reticulated mesh of filaments of synthetic polymer material surrounding the reinforcing core, said spacer being surrounded by said filter septum which is separate from but fits closely about said spacer, and said filter septum being a self-supporting tube of sintered high-density polyethylene.
Claim 2
Dependent Claim
75 words
A filter including a tubular filter septum of porous synthetic polymer material surrounding a reinforcing tubular core comprising coarse grains of synthetic polymer material sintered together, a foraminous tubular spacer formed by a reticulated mesh of filaments of synthetic polymer material surrounding the reinforcing core, said spacer being surrounded by said filter septum which is separate from but fits closely about said spacer, and said filter septum being a self-supporting tube of sintered high-density polyethylene.
Claim 3
Dependent Claim
44 words
A filter as claimed in claim 1 in which said reticulated mesh of filaments is formed by extruding two layers of filaments with the filaments of one layer crossing those of another layer at an angle, intersecting filaments being adhered together where they touch.
Claim 4
Dependent Claim
68 words
A filter as claimed in claim 1 in which the filter septum has a pore size in the range 50 to 130 microns as measured by the method described in British Standard Specification No. 1752:1963, namely measuring the air pressure P required to force the first air bubble through a sheet of the material when completely saturated with n-propanol and determining the pore size d from the equation:
Claim 5
Dependent Claim
68 words
A filter as claimed in claim 1 in which the filter septum has a pore size in the range 60 to 90 microns as measured by the method described in British Standard Specification No. 1752:1963, namely measuring the air pressure P required to force the first air bubble through a sheet of the material when completely saturated with n-propanol and determining the pore size d from the equation
Claim 6
Dependent Claim
108 words
A filter including a tubular filter septum of porous synthetic polymer material surrounding a reinforcing tubular core comprising coarse grains of synthetic polymer material sintered together, a foraminous tubular spacer formed by a reticulated mesh of filaments of synthetic polymer material surrounding the reinforcing core, said spacer being surrounded by said filter septum which is separate from but fits closely about said spacer, said spacer being formed by extruding two layers of filaments with the filaments of one layer crossing those of another layer at an angle, intersecting filaments being adhered together where they touch, and said filter septum being a self-supporting tube of sintered high density polyethylene.
Claim 7
Dependent Claim
108 words
A filter including a tubular filter septum of porous synthetic polymer material surrounding a reinforcing tubular core comprising coarse grains of synthetic polymer material sintered together, a foraminous tubular spacer formed by a reticulated mesh of filaments of synthetic polymer material surrounding the reinforcing core, said spacer being surrounded by said filter septum which is separate from but fits closely about said spacer, said spacer being formed by extruding two layers of filaments with the filaments of one layer crossing those of another layer at an angle, intersecting filaments being adhered together where they touch, and said filter septum being a self-supporting tube of sintered high density polyethylene.
References Cited (Backward Citations)
AT154850B
Cited
US2711828A
Cited
GB943642A
Cited
AU246461A
Cited
US3156645A
Cited
US3441143A
Cited
US3455459A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-18 | 1974-07-20 | 1975-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-18 | 1978-07-20 | 1979-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-18 | 1982-07-20 | 1983-01-19 | $7700.00 | Window Closed / Lapsed |