US3577785A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transducer cleaning device
Assignee: F Hoffmann La Roche AG
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Filing: 1969-06-11
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Granted: 1971-05-04
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Expires: 1989-06-11
Abstract
Abstract A measuring instrument comprising, in a tube, a column of an electrically conductive liquid having a height which is responsive to the input parameter to be measured, an electrical circuit to transform the height of the liquid column into an electrical output value by measuring the voltage drop across the nonimmersed part of a current-carrying wire extending through the tube, and maintaining exact longterm performance of the wire by providing an application of heat thereto thereby preventing contamination of the wire which would otherwise cause nonlinearities between input and output values.
Inventors
- 👤 Lawrence Norayr Guevrekian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:31
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0091; G01L9/0092; G01F; G01F23/00; G01F23/22; G01F23/24; G01L9/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
102 words
A measuring instrument of the type containing in a tube a column of an electrically conductive liquid, measuring means energizable for transforming the height of the column into an electrical value, said measuring means including a resistance wire extending through the tube and a first current supply means having a first current value to feed an electrical current to said resistance wire, and characterized by a second current supply means connected with said resistance wire and periodicAlly energizable to supply a second current value which exceeds said first current value for removing undesirable contaminants from the wire surface by application of heat.
Claim 2
Dependent Claim
102 words
A measuring instrument of the type containing in a tube a column of an electrically conductive liquid, measuring means energizable for transforming the height of the column into an electrical value, said measuring means including a resistance wire extending through the tube and a first current supply means having a first current value to feed an electrical current to said resistance wire, and characterized by a second current supply means connected with said resistance wire and periodicAlly energizable to supply a second current value which exceeds said first current value for removing undesirable contaminants from the wire surface by application of heat.
Claim 3
Dependent Claim
109 words
A measuring instrument of the type containing in a tube column of an electrically conductive liquid, measuring means energizable for transforming the height of the column into an electrical value, said measuring means including a resistance wire extending through the tube and current supply means to feed an electrical current to said resistance wire, and characterized by means for removing contaminants from the wire surface by application of heat wherein said means for removing contaminants comprises cleaning current supply means operable to deliver sufficient current for cleaning said wire and associated means ensuring that the liquid column is at its lowest level during the operation of said cleaning current.
Claim 4
Dependent Claim
109 words
A measuring instrument of the type containing in a tube column of an electrically conductive liquid, measuring means energizable for transforming the height of the column into an electrical value, said measuring means including a resistance wire extending through the tube and current supply means to feed an electrical current to said resistance wire, and characterized by means for removing contaminants from the wire surface by application of heat wherein said means for removing contaminants comprises cleaning current supply means operable to deliver sufficient current for cleaning said wire and associated means ensuring that the liquid column is at its lowest level during the operation of said cleaning current.
Claim 5
Dependent Claim
31 words
A measuring instrument according to claim 2 in which said cleaning current supply means includes timer means to control the duration of the application of said cleaning current to remove contaminants.
Claim 6
Dependent Claim
37 words
A measuring instrument according to claim 3 including means connected with said cleaning current supply means to set said cleaning current supply means into operation every time the measuring instrument is energized to perform its measuring function.
Claim 7
Dependent Claim
72 words
A measuring instrument according to claim 2 wherein the height of said electrically conductive liquid is responsive to fluid pressure means and where said associated means comprises valve means actuable for freeing said conductive liquid from said fluid pressure means to maintain the conductive liquid at a low level, and timer means for actuating said valve means for a period at least coextensive with that of the operation of said cleaning current.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |