US3626284A
Expired / Lapsed
US
⏱️ 0.0 years remaining
An apparatus for measuring changes in microwave frequencies corresponding to the density of a fluid
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1969-08-07
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Granted: 1971-12-07
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Expires: 1989-08-07
Abstract
Abstract An apparatus for measuring the density of a dielectric fluid retained in a vessel. A waveguide is inserted into the liquid through a sealed opening in the vessel. The waveguide has a center conductor concentrically positioned in the waveguide. The center conductor carries a microwave frequency emitted from a source to a disc on the bottom of the waveguide where a fixed node of the microwave frequency occurs. A detector member immersed in the fluid is fixed to the waveguide a predetermined distance from the bottom of the waveguide to receive a node of the standing wave created by the microwave frequency. With a change in the fluid density, the node adjacent the detector member will correspondingly shift with the detector member receiving a different electromagnetic field intensity created by a microwave energy source transmitted through the waveguide. The detector member will communicate all measurements of the electromagnetic field intensity to an indicator where density changes can be directly read from a scale.
Inventors
- 👤 Aloysius Bak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:37
CPC Classifications
G; G01; G01N; G01N22/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
252 words
An apparatus for directly measuring any change in the density of a fluid, comprising: a vessel for holding a quantity of said fluid; waveguide means having one end which extends through an orifice in said vessel and into said fluid, said vessel retaining said waveguide means in a fixed position in said fluid, said waveguide means having openings therein to permit said fluid to freely pass to the interior thereof; means connected to the other end of said waveguide means for emitting microwave energy into said waveguide means at a predetermined frequency; shorting means located in the interior of said waveguide means for creating a fixed node position for the frequency of the microwave emitted within said waveguide; and detector means secured to said waveguide means in said fluid a predetermined distance from said shorting means, said predetermined distance being selected for the frequency of the microwave to create a standing node adjacent said detector means, said detector means measuring the electromagnetic field created by said microwave energy in said fluid as a function of said standing node, said standing node shifting along the interior of said waveguide means with a change in the frequency of the emitted microwave energy caused by a variance in the density of the fluid in the vessel, said node-shifting creating a different electromagnetic field within the interior of said waveguide means, said detector means responding to said shifting in the standing node to indicate a corresponding change in the density of the fluid in the vessel.
Claim 2
Independent Claim
252 words
An apparatus for directly measuring any change in the density of a fluid, comprising: a vessel for holding a quantity of said fluid; waveguide means having one end which extends through an orifice in said vessel and into said fluid, said vessel retaining said waveguide means in a fixed position in said fluid, said waveguide means having openings therein to permit said fluid to freely pass to the interior thereof; means connected to the other end of said waveguide means for emitting microwave energy into said waveguide means at a predetermined frequency; shorting means located in the interior of said waveguide means for creating a fixed node position for the frequency of the microwave emitted within said waveguide; and detector means secured to said waveguide means in said fluid a predetermined distance from said shorting means, said predetermined distance being selected for the frequency of the microwave to create a standing node adjacent said detector means, said detector means measuring the electromagnetic field created by said microwave energy in said fluid as a function of said standing node, said standing node shifting along the interior of said waveguide means with a change in the frequency of the emitted microwave energy caused by a variance in the density of the fluid in the vessel, said node-shifting creating a different electromagnetic field within the interior of said waveguide means, said detector means responding to said shifting in the standing node to indicate a corresponding change in the density of the fluid in the vessel.
Claim 3
Dependent Claim
28 words
The apparatus, as recited in claim 1, further including: indicating means responsive to said detector means for providing evidence of a change in the density of the fluid.
Claim 4
Dependent Claim
51 words
The apparatus, as recited in claim 2, wherein said indicating means includes: a pointer member retained in a housing over a numerical scale, said pointer member being responsive to the change in electromagnetic field intensity measured by said detector to give an operator a visual indication of any fluid density change.
References Cited (Backward Citations)
US3403335A
Cited
US3474337A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |