Patent US3901239A successfully refreshed from Google Patents.
US5036701A
Expired / Lapsed
US
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Mass-flow meter with temperature sensors
Assignee: Bronkhorst High-Tech BV
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Filing: 1990-02-21
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Granted: 1991-08-06
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Expires: 2010-02-21
Abstract
Abstract Mass-flow meter with temperature sensors, designed for measuring mass flow rates of liquids or gases, containing a heat conductive tube, through which the mass flow to be measured occurs and of which the beginning and the end are kept at the same temperature, as well as one or more means to raise the temperature in the tube and means to measure the temperature of the mass in the tube in different places. In or on the tube one or more facilities are applied with which the zero-offset of the means to measure the temperature can be eliminated in a physical instead of an electronic way.
Inventors
- 👤 Frederik Van Der Graaf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:30
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/68; G01F1/684; G01F1/688; G01F1/6888; G01F1/6847
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
A mass-flow meter with temperature sensors adapted for measuring mass flow rates of liquids or gases, having: (a) a heat conductive tube through which the mass flow to be measured occurs and of which the beginning and the end are kept at the same temperature, (b) means to raise the temperature in the tube, (c) means to measure the temperature of the mass in the tube at different places including a plurality of temperature sensors placed symmetrically in relation to the temperature-raising means, characterized in that (d) said means to raise the temperature including electrically-responsive means fixed to the tube for modifying the temperature profile along the tube such that when the tube with an immobile mass is heated said temperature sensors show a temperature difference equal to zero.
Claim 2
Dependent Claim
129 words
A mass-flow meter with temperature sensors adapted for measuring mass flow rates of liquids or gases, having: (a) a heat conductive tube through which the mass flow to be measured occurs and of which the beginning and the end are kept at the same temperature, (b) means to raise the temperature in the tube, (c) means to measure the temperature of the mass in the tube at different places including a plurality of temperature sensors placed symmetrically in relation to the temperature-raising means, characterized in that (d) said means to raise the temperature including electrically-responsive means fixed to the tube for modifying the temperature profile along the tube such that when the tube with an immobile mass is heated said temperature sensors show a temperature difference equal to zero.
Claim 3
Dependent Claim
44 words
A mass-flow meter according to claim 1, characterized in that the electrically-responsive means comprises a heating element in the middle of the tube, said heating element comprising two parts to be controlled separately, said parts being located respectively downstream and upstream of the middle.
Claim 4
Dependent Claim
23 words
A mass-flow meter according to claim 2, characterized in that the temperature measuring means comprise thermocouples having a hot and a cold part.
Claim 5
Dependent Claim
68 words
A mass-flow meter according to claim 3, characterized in that the heat conductive tube is U-shaped, the heating element is mounted around the tube, approximately at the middle of the curve of the U-shaped, the distance between both legs of the U is just equal to the distance between the hot and cold parts of the thermocouples, the thermocouples being clasped between both legs of the U-shaped tube.
Claim 6
Dependent Claim
23 words
A mass-flow meter according to claim 3, characterized in that the hot and cold sides of the thermocouples are about 2.5 mm apart.
Claim 7
Dependent Claim
21 words
A mass-flow meter according to claim 1, characterized in that said electrically-responsive means comprise adjacent heating coils with a center tap.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-08-05 | 1995-02-04 | 1995-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-05 | 1999-02-04 | 1999-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-05 | 2003-02-04 | 2003-08-06 | $7700.00 | Window Closed / Lapsed |