US4828007A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for selectively compressing granular material in a molding box
Assignee: Georg Fischer AG
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Filing: 1988-12-05
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Granted: 1989-05-09
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Expires: 2008-12-05
Abstract
Abstract Granular material is selectively compressed in a molding box by a series of pressure surges applied over the granular material.
Inventors
- 👤 Kurt Fischer
- 👤 Hans Leutwiler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:21
CPC Classifications
B; B22; B22C; B22C15/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
211 words
A process for compressing granular material in a molding box having a pattern plate, a casting pattern on said pattern plate and a mold frame mounted on said pattern plate so as to define therewith a mold cavity around said casting pattern comprising the steps of: (a) feeding said granular material to said mold cavity such that said granular material surrounds and covers said casting pattern thereby forming a surface layer of said granular material; (b) applying a first pressure surge D1 of compressed medium to said surface layer of said granular material at a first rate of pressure change over time so as to produce a first pressure p1 over said material wherein said granular material fills any irregularities in the casting pattern; (c) reducing the pressure over said material to a level p3; (d) thereafter applying a second pressure surge D2 of compressed medium to said surface layer of said granular material at a second rate of pressure change over time so as to produce a second pressure p2 over said material wherein said granular material is compressed wherein said second rate of pressure change over time is greater than said first rate of pressure change over time; and (e) reducing the pressure over said material to atmospheric pressure.
Claim 2
Dependent Claim
211 words
A process for compressing granular material in a molding box having a pattern plate, a casting pattern on said pattern plate and a mold frame mounted on said pattern plate so as to define therewith a mold cavity around said casting pattern comprising the steps of: (a) feeding said granular material to said mold cavity such that said granular material surrounds and covers said casting pattern thereby forming a surface layer of said granular material; (b) applying a first pressure surge D1 of compressed medium to said surface layer of said granular material at a first rate of pressure change over time so as to produce a first pressure p1 over said material wherein said granular material fills any irregularities in the casting pattern; (c) reducing the pressure over said material to a level p3; (d) thereafter applying a second pressure surge D2 of compressed medium to said surface layer of said granular material at a second rate of pressure change over time so as to produce a second pressure p2 over said material wherein said granular material is compressed wherein said second rate of pressure change over time is greater than said first rate of pressure change over time; and (e) reducing the pressure over said material to atmospheric pressure.
Claim 3
Dependent Claim
45 words
A process according to claim 1 wherein said first pressure surge D1 has a pressure increase gradient of α 1 (dp/dt) and said second pressure surge D2 has a pressure increase gradient of α 2 (dp/dt) where α is the angle of the pressure gradient.
Claim 4
Dependent Claim
11 words
A process according to claim 2 wherein α 1 (dp/dt)≦300 bars/second.
Claim 5
Dependent Claim
11 words
A process according to claim 2 wherein α 1 (dp/dt)≦40 bars/second.
Claim 6
Dependent Claim
24 words
A process according to claim 1 wherein p1>p3, p2>p3 and the difference between p1 and p2 is less than or equal to 20 bar.
Claim 7
Dependent Claim
25 words
A process according to claim 1 wherein said first pressure surge D1 and said second pressure surge D2 are generated from a common pressure chamber.
Claim 8
Dependent Claim
24 words
A process according to claim 1 wherein said first pressure surge D1 and said second pressure surge D2 are generated from different pressure chambers.
Claim 9
Dependent Claim
29 words
A process according to claim 6 wherein said common pressure chamber is provided with a first nozzle and a second nozzle for generating said first and second pressure surges.
Claim 10
Dependent Claim
25 words
A process according to claim 6 wherein said common pressure chamber is provided with a single nozzle for generating said first and second pressure surges.
Claim 11
Dependent Claim
25 words
A process according to claim 1 wherein said second rate of pressure change over time is twice said first rate of pressure change over time.
Claim 12
Dependent Claim
11 words
A process according to claim 1 wherein α 1 (dp/dt)≦300 bars/second.
Claim 13
Dependent Claim
11 words
A process according to claim 1 wherein α 1 (dp/dt)≦40 bars/second.
Claim 14
Dependent Claim
24 words
A process according to claim 2 wherein p1>p3, p2>p3 and the difference between p1 and p2 is less than or equal to 20 bar.
Claim 15
Dependent Claim
11 words
A process according to claim 10 wherein α 1 (dp/dt)≦300 bars/second.
Claim 16
Dependent Claim
11 words
A process according to claim 10 wherein α 1 (dp/dt)≦40 bars/second.
Claim 17
Dependent Claim
24 words
A process according to claim 10 wherein p1>p3, p2>p3 and the difference between p1 and p2 is less than or equal to 20 bar.
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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) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |