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US3832430A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for the expression of expandable granules of thermoplastic materials in particular polystyrene

Assignee: Saint Gobain Industries SA
•
Filing: 1968-12-11
•
Granted: 1974-08-27
•
Expires: 1988-12-11
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Abstract

Abstract Method for the expansion of granules of thermoplastic material, particularly polystyrene. The discrete granules are fed into the upper end of a tower or drum and allowed to descend by gravity while under agitation. While so descending they are insufflated with jets of saturated or superheated steam which surrounds each granule and causes it to expand to a final density as low as 4 kg/m3. The granules may be preheated before insufflation with steam, as by entraining them in a stream of heated air which also deposits them into the top of a tower. Or they may be preheated by moving them in a layer between confronting runs of upper and lower foraminous conveyor belts while directing heated air through the layer. When an inclined drum is used the discrete granules are introduced into the elevated end of the rotating drum and agitated while being insufflated with steam dispersed into the drum in a large number of jets distributed in and along its axis of rotation.

Inventors

  • 👤 J Noziere

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 03:58
CPC Classifications
B; B29; B29C; B29C67/00; B29C67/20; B29C44/00; B29C44/34; B29C44/3461; Y; Y10; Y10S; Y10S264/00; Y10S264/09

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 45 words
The method of claim 1, the flow of granules being verticallY downwardly in and along a tower defining said enclosed, confined space, insufflating steam being directed in a plurality of radial jets at each said level, from locations adjacent the peripheral walls of the tower.
Claim 2
Dependent Claim 46 words
The method of claim 1, and preheating the granules by entraining them in heated air, passing the heated air and entrained granules into said enclosed space, there separating the granules from the air, dispensing them into said space, and exhausting the heated air from the space.
Claim 3
Dependent Claim 12 words
The method of claim 3, and reheating and recirculating the exhausted air.
Claim 4
Dependent Claim 35 words
The method of claim 1, continuously forming the granules into a porous layer of uniform thickness, passing heated fluid through the layer to preheat the granules, and introducing the preheated granules continuously into said space.
Claim 5
Dependent Claim 59 words
The method of claim 1, said enclosed space having an axis of symmetry inclined downwardly to the vertical at less than 90* in the direction of flow of granules therethrough, and rotating the space about said inclined axis to agitate the granules while being insufflated with steam dispersed into the space in the form of a multiplicity of jets.
Claim 6
Dependent Claim 16 words
The method of claim 6, said jets being dispersed radially outwardly from and along said axis.

References Cited (Backward Citations)

CA595166A Cited
CA688154A Cited
CA706305A Cited
US2543987A Cited
US2642273A Cited
DE1134504B Cited
US3046607A Cited
US3252228A Cited
US3262686A Cited
US3347961A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-08-26 1978-02-25 1978-08-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-08-26 1982-02-25 1982-08-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-08-26 1986-02-25 1986-08-27 $7700.00 Window Closed / Lapsed

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