US4021346A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter for plastic extruding machine
Assignee: Individual
•
Filing: 1975-03-17
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Granted: 1977-05-03
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Expires: 1995-03-17
Abstract
Abstract Apparatus for filtering heat-softened plastic material under pressure of extrusion comprising a substantially continuous screen with screw means for positively moving the same past the filtering area, said screw means being located in a passage open to the fluid plastic material, with means to harden the plastic material in the passage into a nut in which the filter is embedded. The screw means also functions to prevent the solidified slug (nut) from escaping, preventing leakage.
Inventors
- 👤 Robert L. Berthiaume
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:00
CPC Classifications
B; B01; B01D; B01D29/00; B01D29/09; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/69; B29C48/692; B29C48/03
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
141 words
Apparatus for filtering heat-softened plastic material, comprising a chamber through which the heat-softened material is forced to flow unidirectionally, a transverse passage including said chamber, filter means in the form of a generally continuous screen located in said passage to travel generally at least in part across the flow of the softened material through the chamber, inlet and outlet ports for the screen, the heat-softened material entering said passage, means to cool the heat-softened material to a hardened state in which the screen filter is embedded, a unidirectional rotatable screw located in the passage and engaging said hardened material and forcing the same in a direction causing the embedded screen to move in said direction presenting a new increment of filter to the chamber, and means to rotate the screw unidirectionally, said screw being wholly embedded in the hardened plastic material.
Claim 2
Dependent Claim
141 words
Apparatus for filtering heat-softened plastic material, comprising a chamber through which the heat-softened material is forced to flow unidirectionally, a transverse passage including said chamber, filter means in the form of a generally continuous screen located in said passage to travel generally at least in part across the flow of the softened material through the chamber, inlet and outlet ports for the screen, the heat-softened material entering said passage, means to cool the heat-softened material to a hardened state in which the screen filter is embedded, a unidirectional rotatable screw located in the passage and engaging said hardened material and forcing the same in a direction causing the embedded screen to move in said direction presenting a new increment of filter to the chamber, and means to rotate the screw unidirectionally, said screw being wholly embedded in the hardened plastic material.
Claim 3
Dependent Claim
26 words
The device of claim 1 wherein the outlet port for the filter is also for exit of the hardened material under the influence of said screw.
Claim 4
Dependent Claim
16 words
The apparatus of claim 2 including cooling means at the inlet port and the outlet port.
Claim 5
Dependent Claim
20 words
The apparatus of claim 1 including a second screw, said screw being located one at each side of the chamber.
Claim 6
Dependent Claim
22 words
The apparatus of claim 1 including a shaft extending across the chamber, said screw being mounted on said shaft and driven thereby.
Claim 7
Dependent Claim
17 words
The apparatus of claim 5, wherein a second screw is located in spaced relation on the shaft.
Claim 8
Dependent Claim
140 words
In a filter for a plastic extrusion machine wherein the filter is substantially endless, that improvement which comprises a chamber, a screw located in the chamber to which the molten plastic melt stream has access, inlet and outlet ports in the chamber for the filter, the filter passing through the chamber and becoming embedded in the plastic flowing into the chamber, and means for controlling the temperature of the plastic so that it freezes with the filter and screw embedded therein, forming a plastic nut completely about the screw, means to unidirectionally rotate the nut together with the filter to present a new filtration portion of the screen to the melt stream by turning the screw and separating the plastic nut from its cavity walls, the fluid plastic material then forming an additional nut which also embeds the filter therein.
Claim 9
Dependent Claim
140 words
In a filter for a plastic extrusion machine wherein the filter is substantially endless, that improvement which comprises a chamber, a screw located in the chamber to which the molten plastic melt stream has access, inlet and outlet ports in the chamber for the filter, the filter passing through the chamber and becoming embedded in the plastic flowing into the chamber, and means for controlling the temperature of the plastic so that it freezes with the filter and screw embedded therein, forming a plastic nut completely about the screw, means to unidirectionally rotate the nut together with the filter to present a new filtration portion of the screen to the melt stream by turning the screw and separating the plastic nut from its cavity walls, the fluid plastic material then forming an additional nut which also embeds the filter therein.
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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) | 1980-05-02 | 1980-11-01 | 1981-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-02 | 1984-11-01 | 1985-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-02 | 1988-11-01 | 1989-05-03 | $7700.00 | Window Closed / Lapsed |