US3733902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Minimum length high quality differential pressure producing flow meter
Assignee: SPX Technologies Inc
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Filing: 1972-08-09
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Granted: 1973-05-22
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Expires: 1992-08-09
Abstract
Abstract The disclosure concerns fluid flow metering devices of the differential pressure producing type comprising a tube which defines a throat and a converging section for guiding fluid thereto from an inlet region of larger cross section. The tube has a special converging section which accelerates the fluid at two different rates and causes it to form two vena contractas before it reaches a true static pressure tap in the throat. The tube is designed in accordance with specified dimensional relationships which provide a tube of minimum length preferably having a discharge coefficient of 0.98 and a ''''2 sigma'''' accuracy tolerance between + OR - 0.5 percent and + OR - 1 percent depending upon whether the tube has a circular or a polygonal cross section.
Inventors
- 👤 D Halmi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:04
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/34; G01F1/36; G01F1/40; G01F1/44
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
169 words
A flow metering device of the differential pressure producing type comprising a. a tube which defines a throat and a converging section which guides fluid thereto from an inlet region of larger cross section, b. the converging section having adjoining upstream and downstream portions which accelerate the fluid at different rates and each of which has an edge at its exit end which causes the fluid to form a vena contracta, c. the axial length of the upstream portion being between 0.5 square root AI (0.67-0.76B) and 2.0 square root AI (0.670.76B) and the axial length of the downstream portion being between 0.3 square root AT and 0.9 square root AT, and the axial length of the throat being between 0.4 square root AT and 1.4 square root AT, where AI and AT are the cross sectional areas of the inlet region and the throat, respectively, and B is the Beta ratio of the tube; and d. a true static pressure tap located in the middle of the throat.
Claim 2
Dependent Claim
169 words
A flow metering device of the differential pressure producing type comprising a. a tube which defines a throat and a converging section which guides fluid thereto from an inlet region of larger cross section, b. the converging section having adjoining upstream and downstream portions which accelerate the fluid at different rates and each of which has an edge at its exit end which causes the fluid to form a vena contracta, c. the axial length of the upstream portion being between 0.5 square root AI (0.67-0.76B) and 2.0 square root AI (0.670.76B) and the axial length of the downstream portion being between 0.3 square root AT and 0.9 square root AT, and the axial length of the throat being between 0.4 square root AT and 1.4 square root AT, where AI and AT are the cross sectional areas of the inlet region and the throat, respectively, and B is the Beta ratio of the tube; and d. a true static pressure tap located in the middle of the throat.
Claim 3
Dependent Claim
48 words
A flow metering device as defined in claim 1 in which the axial length of the upstream portion is between Square Root AI (0.67-0.76B) and 1.1 Square Root AI(0.67-0.76B) and the axial length of the downstream portion is between 0.5 Square Root AT and 0.6 Square Root AT.
Claim 4
Dependent Claim
63 words
A flow metering device as defined in claim 2 in which a. the tube also defines an inlet section which is joined to the throat by the converging section; and b. the inlet section contains a true static pressure tap spaced axially from the entrance of the converging section a distance between 0.28 Square Root AI (B-0.31) and 2.0 Square Root AI (B-0.31).
Claim 5
Dependent Claim
25 words
A flow metering device as defined in claim 3 in which the tap is at least 1 inch from the entrance of the inlet section.
Claim 6
Dependent Claim
40 words
A flow metering device as defined in claim 1 in which the tube also defines a diffuser joined to the exit end of the throat and having an axial length up to (6 Square Root AI/0.78 - Square Root AT/0.78).
Claim 7
Dependent Claim
40 words
A flow metering device as defined in claim 3 in which the tube also defines a diffuser joined to the exit end of the throat and having an axial length up to (6 Square Root AI/0.78 - Square Root AT/0.78).
Claim 8
Dependent Claim
40 words
A flow metering device as defined in claim 4 in which the tube also defines a diffuser joined to the exit end of the throat and having an axial length up to (6 Square Root AI/0.78 - Square Root AT/0.78).
Claim 9
Dependent Claim
42 words
A flow metering device as defined in claim 7 in which a. the tube has a circular cross section; b. the inlet section and the throat are cylindrical; and c. the two portions of the converging section and the diffuser are conical.
Claim 10
Dependent Claim
43 words
A flow metering device as defined in claim 7 in which a. the tube has a rectangular cross section; and b. each of the taps is located in a tube wall having a portion in the converging section which changes direction of flow.
Claim 11
Dependent Claim
34 words
A flow metering device as defined in claim 9 in which a. the tube comprises two parallel walls and two shaped walls; and b. the taps are located in one of the shaped walls.
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) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |