Patent US2693901A successfully refreshed from Google Patents.
US4134552A
Expired / Lapsed
US
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Grinding machines
Assignee: Simon Barron Ltd
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Filing: 1977-09-12
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Granted: 1979-01-16
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Expires: 1997-09-12
Abstract
Abstract A grinding mill of the kind comprising a generally cylindrical grinding chamber defined by a screen having a shaft supporting a plurality of grinding hammers rotatable therein and being enclosed in a chamber to which suction is applied characterized by the provision of instrumentality for sensing the pressure within the enclosure surrounding the screen and actuating a safety device in the event that the pressure falls below a pre-determined value.
Inventors
- 👤 Stewart P. T. Fraser
- 👤 Paul A. Fellowes-Freeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:19
CPC Classifications
B; B02; B02C; B02C13/00; B02C13/26; B02C13/288; B02C13/31
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
87 words
A grinding mill of the kind comprising a generally cylindrical grinding chamber defined by a screen having a shaft supporting a plurality of grinding hammers rotatable therein and being enclosed in a chamber to which suction is applied, and wherein the ground material passes through the screen entrained in an air stream into the surrounding enclosure, characterised by the provision of means for sensing the pressure within the enclosure surrounding the screen and actuating safety means in the event that the pressure falls below a pre-determined value.
Claim 2
Dependent Claim
87 words
A grinding mill of the kind comprising a generally cylindrical grinding chamber defined by a screen having a shaft supporting a plurality of grinding hammers rotatable therein and being enclosed in a chamber to which suction is applied, and wherein the ground material passes through the screen entrained in an air stream into the surrounding enclosure, characterised by the provision of means for sensing the pressure within the enclosure surrounding the screen and actuating safety means in the event that the pressure falls below a pre-determined value.
Claim 3
Dependent Claim
38 words
A grinding mill according to claim 1 wherein said means for sensing the pressure within the enclosure surrounding the screen also operates to actuate said safety means in the event that the pressure rises above a pre-determined value.
Claim 4
Dependent Claim
14 words
A grinding mill according to claim 1 wherein said safety means comprises an alarm.
Claim 5
Dependent Claim
14 words
A grinding mill according to claim 2 wherein said safety means comprises an alarm.
Claim 6
Dependent Claim
21 words
A grinding mill according to claim 1 wherein said safety means comprises means to stop the motor of the grinding mill.
Claim 7
Dependent Claim
21 words
A grinding mill according to claim 2 wherein said safety means comprises means to stop the motor of the grinding mill.
Claim 8
Dependent Claim
67 words
A grinding mill according to claim 1 wherein said pressure sensing means is comprised by a manometer tube containing mercury and a number of electrical contacts at spaced positions in one limb thereof for sensing the level of mercury in said limb and for operating a relay to actuate said safety means in the event that the level of mercury changes by more than a pre-determined amount.
Claim 9
Dependent Claim
67 words
A grinding mill according to claim 2 wherein said pressure sensing means is comprised by a manometer tube containing mercury and a number of electrical contacts at spaced positions in one limb thereof for sensing the level of mercury in said limb and for operating a relay to actuate said safety means in the event that the level of mercury changes by more than a pre-determined amount.
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) | 1982-01-15 | 1982-07-17 | 1983-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-15 | 1986-07-17 | 1987-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-15 | 1990-07-17 | 1991-01-16 | $7700.00 | Window Closed / Lapsed |