Patent US3749536A successfully refreshed from Google Patents.
US3749536A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extrusion die for underwater granulator
Assignee: Oerlikon Barmag AG
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Filing: 1971-12-28
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Granted: 1973-07-31
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Expires: 1991-12-28
Abstract
Abstract An extrusion die for an underwater granulator having a nozzle plate at the face end of the die containing extrusion nozzle bores used for conducting and extruding a hot molten thermoplastic polymer into a cooling medium such as water where the extruded material immediately solidifies and is granulated by a cutter arranged close to the die face, each nozzle bore being provided with at least two axially fixed tubular liners in concentric and radially spaced positions, the innermost liner being a metal tube, and heat insulating means located between at least the outermost tubular liner and the wall of each nozzle bore.
Inventors
- 👤 H Remscheid
- 👤 F Ruppel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:54
CPC Classifications
B; B29; B29B; B29B9/00; B29B9/02; B29B9/06; B29B9/065; B29B7/00; B29B7/30; B29B7/58; B29B7/582; B29B7/80; B29B7/82; B29B7/826; B29C; B29C48/00; B29C48/03; B29C48/05; B29C48/25; B29C48/30; B29C48/345; B29C48/04
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
125 words
In an extrusion die for an underwater granulator having a nozzle plate at the face of the die containing a plurality of elongated extrusion nozzle bores for conducting a hot molten thermoplastic material to be extruded at the die face into a cooling liquid and to be granulated by cutting means arranged close to the die face, the improvement which comprises: at least two essentially concentrical tubular liners mounted within each of said nozzle bores and arranged in a fixed axial position with radial clearance between each other and the wall of the nozzle bore, at least the innermost of said liners being a metal tube; and heat insulating means enclosed between at least the outermost tubular liner and the wall of each nozzle bore.
Claim 2
Dependent Claim
125 words
In an extrusion die for an underwater granulator having a nozzle plate at the face of the die containing a plurality of elongated extrusion nozzle bores for conducting a hot molten thermoplastic material to be extruded at the die face into a cooling liquid and to be granulated by cutting means arranged close to the die face, the improvement which comprises: at least two essentially concentrical tubular liners mounted within each of said nozzle bores and arranged in a fixed axial position with radial clearance between each other and the wall of the nozzle bore, at least the innermost of said liners being a metal tube; and heat insulating means enclosed between at least the outermost tubular liner and the wall of each nozzle bore.
Claim 3
Dependent Claim
19 words
An extrusion die as claimed in claim 1 wherein additional heating insulating means are located between individual tubular liners.
Claim 4
Dependent Claim
38 words
An extrusion die as claimed in claim 1 wherein the innermost tubular liner composed of metal is seated as an annular offset portion of the nozzle bore near the outlet end thereof at the face of the die.
Claim 5
Dependent Claim
27 words
An extrusion die as claimed in claim 1 wherein the tubular liners are supported by at least one bridging means having a plurality of radially extending arms.
Claim 6
Dependent Claim
23 words
An extrusion die as claimed in claim 1 wherein annular collar means support and radially position the tubular liners in their concentric positions.
Claim 7
Dependent Claim
31 words
An extrusion die as claImed in claim 1 wherein a plurality of metal tubes are interconnected near their ends to provide a free gas-tight annular space between each pair of tubes.
Claim 8
Dependent Claim
24 words
An extrusion die as claimed in claim 6 wherein said gas-tight annular space is at least partially evacuated to provide a reduced pressure therein.
Claim 9
Dependent Claim
32 words
An extrusion die as claimed in claim 1 wherein a profiled bridging member with three radially extended arms is mounted within the nozzle bore to radially position all of said tubular liners.
Claim 10
Dependent Claim
34 words
An extrusion die as claimed in claim 8 wherein said radially extended arms are in point contact with the inner wall of the nozzle bore to prevent substantial heat transfer over said bridging member.
Claim 11
Dependent Claim
36 words
An extrusion die as claimed in claim 1 wherein the tubular liners are lockable in their radial and axial positions by means of a plurality of spacing rings on at least one of said tubular liners.
Claim 12
Dependent Claim
28 words
An extrusion die as claimed in claim 10 wherein at least one spacing ring at the feed side of the liner assembly is constructed as a sealing gasket.
Claim 13
Dependent Claim
24 words
An extrusion die as claimed in claim 1 wherein said heat insulating means is a solid material having a low value of thermal conductivity.
Claim 14
Dependent Claim
17 words
An extrusion die as claimed in claim 12 wherein said insulating material is glass wool or asbestos.
Claim 15
Dependent Claim
19 words
An extrusion die as claimed in claim 1 wherein the heat insulating means is a gas or gas mixture.
Claim 16
Dependent Claim
24 words
An extrusion die as claimed in claim 14 wherein said gas or gas mixture is maintained under reduced pressure of less than one atmosphere.
Claim 17
Dependent Claim
19 words
An extrusion die as claimed in claim 1 wherein at least the innermost tubular liner is made of steel.
Claim 18
Dependent Claim
42 words
An extrusion die as claimed in claim 16 wherein all of the tubular liners are constructed as an integrally connected unit composed of steel for removable insertion into said nozzle bore with means to seat said unit concentrically on the bore axis.
References Cited (Backward Citations)
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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) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |