Patent US3668817A successfully refreshed from Google Patents.
US3668817A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shrink tunnel and method of shrinking film on articles
Assignee: WR Grace and Co
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Filing: 1970-05-27
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Granted: 1972-06-13
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Expires: 1990-05-27
Abstract
Abstract This invention is directed to shrink tunnel including an inverted U-shaped housing having a hot air inlet on each side near the bottom thereof and an air outlet below the top of the packages passing through the housing with the inlets and outlets positioned to impinge air against the ends of a package passing through the tunnel and withdraw a large part of the air from the tunnel before it can rise above the top of the package; all as further described herein.
Inventors
- 👤 Sydney George Frederick Bell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:31
CPC Classifications
B; B65; B65B; B65B53/00; B65B53/02; B65B53/06; B65B53/063
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
169 words
A method for heat shrinking a heat shrinkable thermoplastic film about an article comprising forming said film into an open ended and continuous tubular sleeve around the article with the outer ends of the sleeve projecting beyond the article at both open ends to form a package, passing said package through a heat shrink zone with the open ends of the sleeve oriented towards the sides of the zone, directing a relatively horizontal flow of hot air from the bottom part of the sides of the heat shrink zone and from below the medial region of the package against the lower portions of the opposing sides of the package having the open ends of the sleeve, withdrawing a large portion of said hot air from said zone at a height below the top of the article and above said lower portion of said zone, shrinking the projecting open ends of the sleeve more rapidly than the other portions of the film and taut about the ends of the article.
Claim 2
Independent Claim
169 words
A method for heat shrinking a heat shrinkable thermoplastic film about an article comprising forming said film into an open ended and continuous tubular sleeve around the article with the outer ends of the sleeve projecting beyond the article at both open ends to form a package, passing said package through a heat shrink zone with the open ends of the sleeve oriented towards the sides of the zone, directing a relatively horizontal flow of hot air from the bottom part of the sides of the heat shrink zone and from below the medial region of the package against the lower portions of the opposing sides of the package having the open ends of the sleeve, withdrawing a large portion of said hot air from said zone at a height below the top of the article and above said lower portion of said zone, shrinking the projecting open ends of the sleeve more rapidly than the other portions of the film and taut about the ends of the article.
Claim 3
Dependent Claim
98 words
The method of claim 1 wherein the relatively horizontal flow of hot air is in the form of jets of hot air which enter the open ends of the sleeve and balloon the ends of the film out from the article and these ballooned portions of the film are the ends that are shrunk more rapidly than the other portions of the film and substantially flat against the ends of the article and said hot air is withdrawn through at least one outlet positioned below the top of the article and above said lower portion of said zone.
Claim 4
Dependent Claim
14 words
The method of claim 2 wherein the jets of hot air are curtain jets.
References Cited (Backward Citations)
US3330094A
Cited
US3402475A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |