US3923653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for cleaning metallic filters of plastic waste
Assignee: American Induction Heating Corp
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Filing: 1972-09-27
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Granted: 1975-12-02
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Expires: 1992-09-27
Abstract
Abstract A metal filter clogged with polyethylene waste is cleaned by suspending it within an induction heating coil in a nitrogen atmosphere and passing current through the coil so as to first raise the temperature of the filter above the melting temperature of the polyethylene but below the auto ignition temperature of the polyethylene. This heating is continued until the bulk of the plastic melts and falls into a water tank supported below the boil. The current through the coil is then raised to heat the filter above the auto-ignition temperature of the polyethylene causing the remaining plastic on the filter to decompose.
Inventors
- 👤 Jr Paul N Lavins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:06
CPC Classifications
B; B29; B29B; B29B17/00; B29B17/02; B01; B01D; B01D29/00; B01D29/62; B01D29/76; B01D29/80; B01D29/84; B01D29/843; B29C; B29C35/00; B29C35/02; B29C35/08; B29C35/0805; B29C2035/0811; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62; Y10; Y10S; Y10S55/00; Y10S55/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
114 words
The method of removing polyethylene waste from a metallic element comprising suspending the element in an elevated position and inductively heating the element in an atmosphere purged of oxygen to a temperature below the auto-ignition point of the polyethylene but above its melting point until gravity pulls all of said waste with the exception of a thin layer away from said element, wherein melting of the polyethylene will occur only at its interface with the element, and then heating the element to a temperature above the auto-ignition point of the polyethylene for a sufficient period of time to cause decomposition of the remaining polyethylene so that no polyethylene residues remain on the metallic element.
Claim 2
Independent Claim
114 words
The method of removing polyethylene waste from a metallic element comprising suspending the element in an elevated position and inductively heating the element in an atmosphere purged of oxygen to a temperature below the auto-ignition point of the polyethylene but above its melting point until gravity pulls all of said waste with the exception of a thin layer away from said element, wherein melting of the polyethylene will occur only at its interface with the element, and then heating the element to a temperature above the auto-ignition point of the polyethylene for a sufficient period of time to cause decomposition of the remaining polyethylene so that no polyethylene residues remain on the metallic element.
Claim 3
Dependent Claim
33 words
The method of claim 1 wherein a body of liquid is disposed relative to said metallic element so that the polyethylene falling from said element falls into and is quenched by the liquid.
Claim 4
Independent Claim
122 words
THE METHOD OF REMOVING PLASTIC WASTE FROM A METALLIC ELEMENT COMPRISING: SUSPENDING THE ELEMENT IN AN ELEVATED POSITION AND HEATING THE ELEMENT IN AN ATMOSPHERE PURGED OF OXYGEN, BY INDUCTIVE HEATING UNTIL THE ELEMENT REACHES A TEMPERATURE BELOW THE AUTO-IGNITION POINT BUT ABOVE THE MELTING POINT OF THE PLASTIC AND UNTIL GRAVITY PULLS ALL OF THE PLASTIC WITH THE EXCEPTION OF A THIN LAYER AWAY FROM THE ELEMENT WHEREIN MELTING OF THE PLASTIC WILL OCCUR ONLY AT ITS INTERFACE WITH THE ELEMENT, AND THEN HEATING THE ELEMENT AT A TEMPERATURE ABOVE THE AUTO-IGNITION POINT OF THE PLASTIC FOR A SUFFICIENT PERIOD OF TIME TO CAUSE DECOMPOSITION OF THE THIN LAYER OF PLASTIC SO THAT NO PLASTIC RESIDUES REMAIN ON THE METALLIC ELEMENT.
Claim 5
Independent Claim
122 words
THE METHOD OF REMOVING PLASTIC WASTE FROM A METALLIC ELEMENT COMPRISING: SUSPENDING THE ELEMENT IN AN ELEVATED POSITION AND HEATING THE ELEMENT IN AN ATMOSPHERE PURGED OF OXYGEN, BY INDUCTIVE HEATING UNTIL THE ELEMENT REACHES A TEMPERATURE BELOW THE AUTO-IGNITION POINT BUT ABOVE THE MELTING POINT OF THE PLASTIC AND UNTIL GRAVITY PULLS ALL OF THE PLASTIC WITH THE EXCEPTION OF A THIN LAYER AWAY FROM THE ELEMENT WHEREIN MELTING OF THE PLASTIC WILL OCCUR ONLY AT ITS INTERFACE WITH THE ELEMENT, AND THEN HEATING THE ELEMENT AT A TEMPERATURE ABOVE THE AUTO-IGNITION POINT OF THE PLASTIC FOR A SUFFICIENT PERIOD OF TIME TO CAUSE DECOMPOSITION OF THE THIN LAYER OF PLASTIC SO THAT NO PLASTIC RESIDUES REMAIN ON THE METALLIC ELEMENT.
Claim 6
Dependent Claim
31 words
The method of claim 3 wherein the element is supported in an elevated position above a body of liquid so that said plastic falls into and is quenched by said liquid.
Claim 7
Dependent Claim
18 words
The method of claim 3 wherein the atmosphere in which the element is maintained is ventilated during heating.
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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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |