US3665180A
Expired / Lapsed
US
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Method and apparatus for measuring the water content of a snowpack
Assignee: Electricite de France SA
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Filing: 1969-11-25
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Granted: 1972-05-23
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Expires: 1989-11-25
Abstract
Abstract A device for measuring the water content of a snowpack comprises two vertical tubes respectively locating a standard gamma ray source delivering a horizontal beam and a detector. The source and the detector are moved simultaneously in the respective tubes by a step-by-step motor. Each step occurs after a pre-determined number of pulses has been delivered by the detector so that the time interval between two successive movements is proportional to the water content of the snow layer between two successive movements of the source and detector.
Inventors
- 👤 Pierre Guillot
- 👤 Michel Vuillot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:59
CPC Classifications
G; G01; G01N; G01N23/00; G01N23/02; G01N23/06; G01N23/12; G01W; G01W1/00; G01W1/14; G06; G06F; G06F7/00; G06F7/60; G06F7/62
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
82 words
A method of measurement of the water content of a snow pack, comprising displacing a radioactive source and a gamma-radiation detector simultaneously along vertical passageways formed within the snowpack and deducing the water content of the snowpack at a number of different levels from the intensities of the radiation measured by the detector at said levels, wherein the improvement comprises displacing the source and the detector at a mean rate which is variable and proportional to the intensity measureD at each level.
Claim 2
Independent Claim
82 words
A method of measurement of the water content of a snow pack, comprising displacing a radioactive source and a gamma-radiation detector simultaneously along vertical passageways formed within the snowpack and deducing the water content of the snowpack at a number of different levels from the intensities of the radiation measured by the detector at said levels, wherein the improvement comprises displacing the source and the detector at a mean rate which is variable and proportional to the intensity measureD at each level.
Claim 3
Dependent Claim
40 words
A method according to claim 1, wherein the source and detector are displaced by steps, all steps being equal and each displacement occuring after a pre-determined number n of pulses has been emitted by the detector since the preceding displacement.
Claim 4
Dependent Claim
65 words
A method according to claim 2, wherein time intervals are defined each corresponding to the emission by the detector of a given number N of pulses which is equal to n or a multiple thereof and to the scanning of a layer of pre-determined thickness of the snowpack measured, each of said time intervals being representative of the water content of the corresponding snow layer.
Claim 5
Independent Claim
97 words
A device for measuring the water content of a snow pack, comprising: two stationary vertical tubes; a gamma ray source of pre-determined activity; means vertically movable within one of the tubes and emitting a gamma ray beam in a substantial horizontal plane; a radiation detector vertically movable within the other tube; means for moving the detector and the source simultaneously within the two tubes and maintaining them at the same level, and means for controlling said motor and moving said source and said detector at a speed which is proportional to the intensity measured by the detector.
Claim 6
Independent Claim
97 words
A device for measuring the water content of a snow pack, comprising: two stationary vertical tubes; a gamma ray source of pre-determined activity; means vertically movable within one of the tubes and emitting a gamma ray beam in a substantial horizontal plane; a radiation detector vertically movable within the other tube; means for moving the detector and the source simultaneously within the two tubes and maintaining them at the same level, and means for controlling said motor and moving said source and said detector at a speed which is proportional to the intensity measured by the detector.
Claim 7
Dependent Claim
46 words
A device according to claim 4, wherein the motor which serves to actuate the source and the detector is of the step-by-step type and the control means causes a one-step rotation of the motor each time the detector has emitted a given number n of pulses.
Claim 8
Dependent Claim
18 words
A device according to claim 5, wherein the motor is of the reversible step-by-step and contactless magnetic-locking type.
Claim 9
Dependent Claim
30 words
A device according to claim 4 comprising a dividing circuit which is supplied by the detector and delivers a drive pulse to the motor at intervals corresponding to n pulses.
Claim 10
Dependent Claim
44 words
A device according to claim 5 comprising a scaler which is supplied by the detector, said scaler having a capacity N which is a multiple of n or which is equal to n and delivers a time-measurement pulse at each filling of said scaler.
Claim 11
Dependent Claim
62 words
A device according to claim 4 comprising an empty horizontal compartment which is placed between the access tubes and the top face of which is level with the ground, the rest position of the source and of the detector being located at a distance from the top wall of said compartment which is equal to the thickness of one of said layers.
Claim 12
Dependent Claim
69 words
A device according to claim 9 comprising means for automatically stopping the motor and reversing the displacement of said motor until the source and the detector have returned to their position of rest, said means being actuated when within a given measurement layer the time t for counting N pulses is shorter than the time to for counting the same number of pulses at the level of said compartment.
Claim 13
Dependent Claim
82 words
A device according to claim 10 comprising a clock generator, two counters, a circuit which switches the output of the clock generator to the first counter during the time interval to then to the second counter during each successive time interval t and means for reversing the movement of the motor at the instant at which the detector and the source pass through a layer corresponding to N pulses in a time interval t which is shorter than or equal to to.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |