US3783373A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for measuring density and moisture
Assignee: Mpac Group PLC
•
Filing: 1972-02-08
•
Granted: 1974-01-01
•
Expires: 1992-02-08
Abstract
Abstract A device for monitoring density of a rod of tobacco in a cigarette-making machine comprises a source of microwave radiation and a waveguide through which said radiation is propagated in the evanescent mode to a detector. The rod is passed across the path of the radiation, through apertures in the walls of the waveguide. The radiation may be split into two beams, one beam being directed through said waveguide and the other beam directed through a second, similar waveguide to a second detector providing a reference signal.
Inventors
- 👤 T Jawor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:23
CPC Classifications
G; G01; G01N; G01N22/00; A; A24; A24C; A24C5/00; A24C5/32; A24C5/34; A24C5/3412; G01N22/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
250 words
A device for monitoring the density of a rod of tobacco or the like in a continuous rod cigarette-making machine, comprising a source of microwave radiation, a first detector for said radiation, a waveguide providing a path for said radiation from said source to travel to said detector, in which said waveguide includes a portion of such narrow cross-section that said radiation is propagated therethrough in the evanescent mode, said portion of waveguide having apertured walls to permit said rod to be fed across the path of said radiation, a second detector, means in the form of a directional coupler for splitting the radiation from said source into two beams and directing one of said beams into said waveguide, a second similar waveguide arranged to receive the other of said beams and provide a path for said other beam to travel to said second detector, means for comparing output signals delivered by said first detector with oUtput signals delivered by said second detector, a second source of microwave radiation, a further detector, and a further waveguide arranged to receive radiation from said second source and providing a path for said radiation to travel to said further detector, said second source being arranged to operate at a frequency different from that of the first-mentioned source and said further waveguide being arranged to intersect the narrow portion of said waveguide so that said rod can be fed simultaneously across the paths of radiation in both said narrow portion and said further waveguide.
Claim 2
Independent Claim
250 words
A device for monitoring the density of a rod of tobacco or the like in a continuous rod cigarette-making machine, comprising a source of microwave radiation, a first detector for said radiation, a waveguide providing a path for said radiation from said source to travel to said detector, in which said waveguide includes a portion of such narrow cross-section that said radiation is propagated therethrough in the evanescent mode, said portion of waveguide having apertured walls to permit said rod to be fed across the path of said radiation, a second detector, means in the form of a directional coupler for splitting the radiation from said source into two beams and directing one of said beams into said waveguide, a second similar waveguide arranged to receive the other of said beams and provide a path for said other beam to travel to said second detector, means for comparing output signals delivered by said first detector with oUtput signals delivered by said second detector, a second source of microwave radiation, a further detector, and a further waveguide arranged to receive radiation from said second source and providing a path for said radiation to travel to said further detector, said second source being arranged to operate at a frequency different from that of the first-mentioned source and said further waveguide being arranged to intersect the narrow portion of said waveguide so that said rod can be fed simultaneously across the paths of radiation in both said narrow portion and said further waveguide.
Claim 3
Dependent Claim
34 words
A device as claimed in claim 1, in which said second source is arranged to operate at such a frequency that microwave radiation therefrom is propagated through said further waveguide in the normal mode.
Claim 4
Dependent Claim
53 words
A device as claimed in claim 1, including an additional detector, an additional waveguide similar to said further waveguide and providing a path for radiation from said second source to said additional detector, and further means for comparing output signals delivered by said further detector with output signals delivered by said additional detector.
Claim 5
Dependent Claim
25 words
A device as claimed in claim 3, including computing means connected to receive outputs from both the comparing means and from the further comparing means.
Claim 6
Dependent Claim
16 words
A device as claimed in claim 4 in which said computing means is an analogue network.
Claim 7
Dependent Claim
30 words
A device as claimed in claim 3 in which said further waveguide and said additional waveguide are integral with one another and extend in opposite directions from the second source.
References Cited (Backward Citations)
CA656110A
Cited
US2532817A
Cited
US3034046A
Cited
US3060421A
Cited
US3265873A
Cited
US3115131A
Cited
US3265967A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |