US4088724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
External sizing and cooling of extruded tubular profiles of thermoplastic material
Assignee: Hoechst AG
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Filing: 1974-05-09
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Granted: 1978-05-09
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Expires: 1994-05-09
Abstract
Abstract After extrusion tubular profiles of thermoplastic material are sized and cooled by the overpressure method. The internal pressure is produced and cooling effected by evaporation in the hollow space of the profile of a chemically inert liquefied gas having a critical temperature in the range of from -150° to +35° C.
Inventors
- 👤 Johannes Kuhnert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:40
CPC Classifications
F; F25; F25D; F25D3/00; F25D3/10; B; B29; B29C; B29C48/00; B29C48/03; B29C48/09; B29C48/25; B29C48/88; B29C48/90; B29C48/901; B29C48/902; B29C48/903; B29C48/908; B29C48/911; B29C48/9115; B29C48/10; B29C48/885; B29C48/912; B29C48/9135
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
132 words
In the method of sizing and cooling thick walled extruded hollow tubular articles formed of a thermoplastic material by passing the tubular article through an elongated sizing device having inlet and outlet ends and an internal bore through which the article is passed that is generally complementary to the desired external configuration of the article; producing an internal pressure in said tubular article to urge the article against the internal bore of said sizing device, while simultaneously cooling the article as it passes through said sizing device, wherein the improvement comprises producing the internal pressure and cooling the article by spraying and evaporating, within the article, as it passes through said sizing device, a chemically inert liquefied gas having a critical temperature in the range of from -150° C to 35° C.
Claim 2
Dependent Claim
132 words
In the method of sizing and cooling thick walled extruded hollow tubular articles formed of a thermoplastic material by passing the tubular article through an elongated sizing device having inlet and outlet ends and an internal bore through which the article is passed that is generally complementary to the desired external configuration of the article; producing an internal pressure in said tubular article to urge the article against the internal bore of said sizing device, while simultaneously cooling the article as it passes through said sizing device, wherein the improvement comprises producing the internal pressure and cooling the article by spraying and evaporating, within the article, as it passes through said sizing device, a chemically inert liquefied gas having a critical temperature in the range of from -150° C to 35° C.
Claim 3
Dependent Claim
28 words
The process as defined in claim 1 wherein said chemically inert liquefied gas is selected from the group consisting of nitrogen, carbon dioxide, trichlorofluoromethane, difluorodichloromethane, and aliphatic halohydrocarbons.
Claim 4
Dependent Claim
27 words
The method as defined in claim 1 including the step of simultaneously cooling the exterior of said tubular article by passing liquefied gas through said sizing device.
Claim 5
Dependent Claim
62 words
The method as defined in claim 3 wherein said cooling step includes the step of locating radially movable cooling segment elements in said article; and said spraying step comprises spraying the liquefied gas under pressure within said segments to move the segments radially outwardly into contact with the inner wall of said article while simultaneously cooling said segments and the said article.
Claim 6
Dependent Claim
35 words
The method for sizing and cooling as defined in claim 1 wherein the internal pressure is produced in said article with evaporating liquefied gas and the simultaneous introduction into the article of a compressed gas.
Claim 7
Dependent Claim
91 words
The method for sizing and cooling as defined in claim 1 wherein said cooling step includes the step of locating a radiator heat exchange element in said article and said spraying step comprises spraying the liquefied gas within said radiator to evaporate therein and cool the radiator and passing the evaporated gas through the radiator to the space between the inner wall of the article and the radiator; and supplying compressed gas to said space for mixture with the evaporated gas therein, whereby cooling of said article is effected by convection.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |