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US3689192A Expired / Lapsed US ⏱️ 0.0 years remaining

Manufacture of film from thermoplastic material that is blown by a blowhead

Assignee: Windmoeller and Hoelscher KG
•
Filing: 1971-02-23
•
Granted: 1972-09-05
•
Expires: 1991-02-23
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Abstract

Abstract A blowhead for making tubular plastics film in which a housing including an outer part and an inner part having a large central opening for accommodating equipment that is to project into the tubular film is fitted with a nozzle at one end at which the film is blown. Convoluted distributing passages leading to the nozzle are defined between the outer and inner parts of the housing. A lateral supply passage leads molten plastics material to the convoluted distributing passages and includes a cleavage dividing the supply passage into branch passages. The convoluted distributing passages in the direction of the nozzle gradually decrease in depth. Gaps connect adjacent convolutions of the convoluted distributing passages and these gaps in the direction of the nozzle increase in width so that the plastics material as it flows towards the nozzle is gradually led from a convoluted flow path to an axial flow path. Upon introduction the plastics material is distributed as part-streams into the branch passages substantially in a plane which is radial of the blowhead axis and one of the branch passages merges with the associated convoluted distributing passage over a substantially U-shaped bend.

Inventors

  • 👤 Hartmut Upmeier

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 06:48
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/695; B29C48/70; B29C48/705; B29C48/03; B29C48/09; B29C48/10; B29C48/30; B29C48/32; B29C48/34

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 200 words
A blowhead for making tubular plastics film, comprising a housing including an outer part and an inner part having a large central opening for accommodating equipment that is to project into the tubular film, a nozzle at which the film is blown, convoluted distributing passages leading to the nozzle and being defined between the outer and inner parts of the housing, a lateral supply passage in the housing for leading molten plastics material to the convoluted distributing passages including a cleavage dividing the supply passage into branch passages, which branch passages lead to respective convoluted distributing passages, said convoluted distributing passages in the direction of the nozzle gradually decreasing in depth, gaps defined in the housing between adjacent convolutions of the convoluted distributing passages said gaps in the direction of the nozzle increasing in width so that the plastics material as it flows towards the nozzle is gradually led from a convoluted flow path to an axial flow path, and wherein the plastics material is distributed as part-streams into the branch passages substantially in a plane which is radial of the blowhead axis, one of the branch passages merging with the associated convoluted distributing passage over a substantially U-shaped bend.
Claim 2
Dependent Claim 200 words
A blowhead for making tubular plastics film, comprising a housing including an outer part and an inner part having a large central opening for accommodating equipment that is to project into the tubular film, a nozzle at which the film is blown, convoluted distributing passages leading to the nozzle and being defined between the outer and inner parts of the housing, a lateral supply passage in the housing for leading molten plastics material to the convoluted distributing passages including a cleavage dividing the supply passage into branch passages, which branch passages lead to respective convoluted distributing passages, said convoluted distributing passages in the direction of the nozzle gradually decreasing in depth, gaps defined in the housing between adjacent convolutions of the convoluted distributing passages said gaps in the direction of the nozzle increasing in width so that the plastics material as it flows towards the nozzle is gradually led from a convoluted flow path to an axial flow path, and wherein the plastics material is distributed as part-streams into the branch passages substantially in a plane which is radial of the blowhead axis, one of the branch passages merging with the associated convoluted distributing passage over a substantially U-shaped bend.
Claim 3
Dependent Claim 52 words
A blowhead according to claim 1, wherein the supply passage and branch passages are defined by channels of substantially semicircular cross-section in the confronting faces of two superposed plates forming part of the housing, the channels being led to the branch passages in opposite directions at the cleavage without a dividing wall.
Claim 4
Dependent Claim 37 words
A blowhead according to claim 1, wherein the convoluted distributing passages are of substantially 270* sector cross-section at their closed portions up to the start of the gaps and the branch passages are of substantially circular cross-section.

References Cited (Backward Citations)

US3026565A Cited
US3270371A Cited
US3343215A Cited
US3549735A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-09-05 1976-03-06 1976-09-05 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-09-05 1980-03-06 1980-09-05 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-09-05 1984-03-06 1984-09-05 $7700.00 Window Closed / Lapsed

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