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US3596522A
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Second sound measurement of absolute rotational motion
Assignee: Harvest Queen Mill and Elevator Co
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Filing: 1968-04-05
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Granted: 1971-08-03
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Expires: 1988-04-05
Abstract
Abstract A method and apparatus for measuring absolute rotational motion by producing entropy waves in liquid helium II filling a cylindrical container rotationally mounted with respect to a fixed reference. A carbon resistance heater generates an entropy wave beam to a beam splitter where it is divided into two beams progressing oppositely through the liquid helium II at a speed independent of the angular velocity of the container. Reflectors attached to the container reflect the two oppositely directed beams to a detector station where the sense and magnitude of any phase difference between the beams actuates a phase detector. The phase detector produces a signal proportional to the sense and magnitude of the phase difference to a servo loop coupled to adjust the rotational motion of the container.
Inventors
- 👤 Donald L Ensley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:14
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01P; G01P3/00; G01P3/42; G01P3/44
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
141 words
A motion transducer comprising: a superfluid bath within a housing positionable with respect to a fixed reference, said bath having a superfluid component that remains at rest below a critical velocity of said housing, generator means for producing high frequency entropy waves in said bath, reflector means for splitting said waves into two beams oppositely directed through said bath, such that with the housing in an at rest position with respect to the fixed reference, both beams travel substantially an equal distance to a detector station, and means responsive to a phase difference between said beams at the detector station for generating a signal proportional to the sense and magnitude of said phase difference that varies in accordance with the change in distance travelled by said beams as a result of movement of the housing with respect to the fixed reference.
Claim 2
Dependent Claim
141 words
A motion transducer comprising: a superfluid bath within a housing positionable with respect to a fixed reference, said bath having a superfluid component that remains at rest below a critical velocity of said housing, generator means for producing high frequency entropy waves in said bath, reflector means for splitting said waves into two beams oppositely directed through said bath, such that with the housing in an at rest position with respect to the fixed reference, both beams travel substantially an equal distance to a detector station, and means responsive to a phase difference between said beams at the detector station for generating a signal proportional to the sense and magnitude of said phase difference that varies in accordance with the change in distance travelled by said beams as a result of movement of the housing with respect to the fixed reference.
Claim 3
Dependent Claim
30 words
A motion transducer as set forth in claim 1 wherein said superfluid bath is liquid helium II maintained at a temperature on the order of 0.5* K. to 2.2* K.
Claim 4
Dependent Claim
22 words
A motion transducer as set forth in claim 2 wherein said generator means is a carbon resistance heater located within said bath.
Claim 5
Independent Claim
169 words
A system for measuring absolute rational motion comprising: a container rotationally mounted with respect to a fixed reference, a super cold liquid having a superfluid component and a normal component filling said container, said superfluid component remaining at rest below a critical angular velocity of said container, generator means for producing an entropy wave in said super cold liquid, a beam splitter at a wall of said container and movable therewith for splitting said beam into two beams oppositely directed through said super cold liquid, such that with the container in an at rest position with respect to the fixed reference, both beams travel substantially an equal distance to a detector station, and means responsive to the phase difference between said oppositely directed beams at the detector station for generating a signal proportional to the sense and magnitude of said phase difference that varies in accordance with the change in distance travelled by said beams as a result of movement of the container with respect to the fixed reference.
Claim 6
Independent Claim
169 words
A system for measuring absolute rational motion comprising: a container rotationally mounted with respect to a fixed reference, a super cold liquid having a superfluid component and a normal component filling said container, said superfluid component remaining at rest below a critical angular velocity of said container, generator means for producing an entropy wave in said super cold liquid, a beam splitter at a wall of said container and movable therewith for splitting said beam into two beams oppositely directed through said super cold liquid, such that with the container in an at rest position with respect to the fixed reference, both beams travel substantially an equal distance to a detector station, and means responsive to the phase difference between said oppositely directed beams at the detector station for generating a signal proportional to the sense and magnitude of said phase difference that varies in accordance with the change in distance travelled by said beams as a result of movement of the container with respect to the fixed reference.
Claim 7
Dependent Claim
22 words
A system for measuring absolute rotational motion as set forth in claim 4 wherein said super cold liquid is liquid helium II.
Claim 8
Dependent Claim
33 words
A system for measuring absolute rotational motion as set forth in claim 4 including reflector means at said container wall for reflecting said oppositely directed beams through said bath to said detector station.
Claim 9
Dependent Claim
43 words
A system for measuring absolute rotational motion as set forth in claim 6 including servo means responsive to said proportional signal for controlling the angular velocity of said container to maintain a phase null between said oppositely directed beams at the detector station.
Claim 10
Dependent Claim
30 words
A system for measuring absolute rotational motion as set forth in claim 7 wherein said servo means includes an amplifier responsive to the sense and magnitude of said proportional signal.
Claim 11
Independent Claim
174 words
A system for measuring absolute rotational motion comprising: a cylindrical container rotatably mounted with respect to a fixed reference, liquid helium II filling said container having a superfluid component that remains at a rest velocity below a critical angular velocity of said container, generator means for producing an entropy wave in said bath, a beam splitter attached to said container for splitting said wave into two beams oppositely directed through said bath, such that with said container in an at rest position with respect to the fixed reference, both beams travel substantially an equal distance to a detector station, reflector means attached to said cylindrical container for reflecting said oppositely directed beams from said beam splitter to the detector station, and means responsive to the phase difference between said beams at the detector station for generating a signal proportional to the sense and magnitude of said difference that varies in accordance with the change in distance travelled by said beams as a result of movement of said container with respect to the fixed reference.
Claim 12
Independent Claim
174 words
A system for measuring absolute rotational motion comprising: a cylindrical container rotatably mounted with respect to a fixed reference, liquid helium II filling said container having a superfluid component that remains at a rest velocity below a critical angular velocity of said container, generator means for producing an entropy wave in said bath, a beam splitter attached to said container for splitting said wave into two beams oppositely directed through said bath, such that with said container in an at rest position with respect to the fixed reference, both beams travel substantially an equal distance to a detector station, reflector means attached to said cylindrical container for reflecting said oppositely directed beams from said beam splitter to the detector station, and means responsive to the phase difference between said beams at the detector station for generating a signal proportional to the sense and magnitude of said difference that varies in accordance with the change in distance travelled by said beams as a result of movement of said container with respect to the fixed reference.
Claim 13
Dependent Claim
30 words
A system for measuring absolute rotational motion as set forth in claim 9 wherein said entropy wave generator is a shielded resistance heater producing a beam in a fixed direction.
Claim 14
Dependent Claim
24 words
A system for measuring absolute rotational motion as set forth in claim 10 wherein said resistance heater is energized from a 100 kHz. source.
Claim 15
Dependent Claim
49 words
A system for measuring absolute rotational motion as set forth in claim 9 including servo means coupled to said cylindrical container and responsive to said proportional signal to control the angular velocity of said container thereby maintaining a phase null between said oppositely directed beams at said detector station.
Claim 16
Dependent Claim
35 words
A system for measuring absolute rotational motion as set forth in claim 9 wherein said cylindrical container includes windows through which said oppositely directed beams pass from said cylinder after reflection from the detector station.
Claim 17
Independent Claim
122 words
A method of measuring absolute rotational motion comprising the steps of: rotating a container of liquid helium II with respect to a fixed reference, generating an entropy wave in said liquid helium II, splitting said entropy wave into two beams oppositely directed through said helium II such that with the container in an at rest position both beams travel substantially an equal distance to a detector station, and generating a signal at the detector station proportional to the sense and magnitude of the phase difference between said oppositely directed beams that varies in accordance with the change in path length travelled by said beams as a result of rotation of the container of liquid helium II with respect to the fixed reference.
Claim 18
Independent Claim
122 words
A method of measuring absolute rotational motion comprising the steps of: rotating a container of liquid helium II with respect to a fixed reference, generating an entropy wave in said liquid helium II, splitting said entropy wave into two beams oppositely directed through said helium II such that with the container in an at rest position both beams travel substantially an equal distance to a detector station, and generating a signal at the detector station proportional to the sense and magnitude of the phase difference between said oppositely directed beams that varies in accordance with the change in path length travelled by said beams as a result of rotation of the container of liquid helium II with respect to the fixed reference.
Claim 19
Dependent Claim
31 words
A method for measuring absolute rotational motion as set forth in claim 14 including nulling said phase difference by controlling the rotation of said container in response to said proportional signal.
Claim 20
Dependent Claim
28 words
A method of measuring absolute rotational motion as set forth in claim 15 including the step of absorbing said oppositely directed beams after passing from said detector station.
References Cited (Backward Citations)
US3395270A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |