US3856680A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic screen changer for extruding processes
Assignee: Mobil Oil AS
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Filing: 1973-10-15
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Granted: 1974-12-24
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Expires: 1993-10-15
Abstract
Abstract An automatic screen changer for extrusion processes is described comprising a screen backing plate which supports the filter screen and moves transversely to the extruder bore when change of filter is required.
Inventors
- 👤 J Elmore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:49
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/69; B29C48/691; B29C48/6912; B29C48/03; B29C48/07; B29C48/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
200 words
In apparatus for extruding heat softened material wherein a filter screen enclosure having inlet and outlet parts is placed transverse the bore of an extruder housing the flow of heat softened material and periodic change of a filter screen in said filter screen enclosure of said extruder is required without interrupting the flow of heat softened material, the improvement which comprises: a backing plate with spaced apart transverse support bars across the extruder bore in the filter screen enclosure of the extruder, an elongated perfoRated rectangular breaker plate in matching engagement with a strip of filter screen in said inlet and outlet parts of said filter screen enclosure which will move with said screen across said backing plate and said extruder bore, said breaker-plate-screen filter combination passing through said inlet and outlet parts in said filter enclosure provided with adjacent temperature adjusting means and said outlet port sized larger than said inlet port to permit the accumulation of a plug of solidified thermoplastic on the upstream side of the screen which is used under the influence of pressure to transversely move said breaker-plate-screen assembly when solidified thermoplastic material is softened in the inlet and outlet ports of said screen enclosure.
Claim 2
Dependent Claim
200 words
In apparatus for extruding heat softened material wherein a filter screen enclosure having inlet and outlet parts is placed transverse the bore of an extruder housing the flow of heat softened material and periodic change of a filter screen in said filter screen enclosure of said extruder is required without interrupting the flow of heat softened material, the improvement which comprises: a backing plate with spaced apart transverse support bars across the extruder bore in the filter screen enclosure of the extruder, an elongated perfoRated rectangular breaker plate in matching engagement with a strip of filter screen in said inlet and outlet parts of said filter screen enclosure which will move with said screen across said backing plate and said extruder bore, said breaker-plate-screen filter combination passing through said inlet and outlet parts in said filter enclosure provided with adjacent temperature adjusting means and said outlet port sized larger than said inlet port to permit the accumulation of a plug of solidified thermoplastic on the upstream side of the screen which is used under the influence of pressure to transversely move said breaker-plate-screen assembly when solidified thermoplastic material is softened in the inlet and outlet ports of said screen enclosure.
Claim 3
Dependent Claim
35 words
The apparatus of claim 1 in which said breaker plate is provided with rows of holes therethrough which rows of holes are aligned with the space between the transverse support bars of the backing plate.
Claim 4
Dependent Claim
39 words
The apparatus of claim 1 in which the breaker plate is provided with a transverse groove adjacent the end thereof which will accept the transverse lip on the end of a second breaker plate brought in matching contact therewith.
Claim 5
Dependent Claim
31 words
The apparatus of claim 1 in which the breaker plate is provided with a recessed portion throughout the length and width thereof within which recessed portion a filter screen is retained.
Claim 6
Dependent Claim
47 words
The apparatus of claim 1 in which the filter screen is moved with its matching adjacent breaker plate across the extruder bore by a controlled force and temperature adjusted conditions when the screen collects impurities in an amount raising the extruding pressure in excess of 5,000 psi.
References Cited (Backward Citations)
US3471017A
Cited
US3443693A
Cited
US3471023A
Cited
US3615257A
Cited
US3645309A
Cited
US3645401A
Cited
US3743101A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |