US3975967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion resistant Bourdon tube
Assignee: Dresser Industries Inc
•
Filing: 1975-04-21
•
Granted: 1976-08-24
•
Expires: 1995-04-21
Abstract
Abstract A corrosion resistant Bourdon tube for pressure gauges and the like formed of a vacuum purified ferritic stainless steel containing by weight about 26 percent chromium, about 1 percent molybdenum and ultra-low carbon and nitrogen content on the order of about 0.002 and 0.008 percent, respectively. By virtue of the metallurgical structure of this composition affording good weldability and ductility, a Bourdon tube fabricated therefrom is characterized by substantial immunity to chloride stress cracking, and high resistance to both sulfide damage and pitting corrosion.
Inventors
- 👤 Jack Conti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:49
CPC Classifications
G; G01; G01L; G01L7/00; G01L7/02; G01L7/04; G01L7/041
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
100 words
In a pressure sensitive instrument including a Bourdon tube operatively responsive to effect an output position change in correlation to changes in pressure from a source with which it is connected, the improvement in which said Bourdon tube is comprised of an iron chromium alloy obtained from a vacuum purification process and having a predominantly ferritic microstructure at room temperature consisting essentially of at least about 24 percent by weight chromium, at least about 1/2 percent by weight molybdenum, less than about 250 p.p.m. combined carbon plus nitrogen and the balance iron while being essentially free of volatile metallic impurities.
Claim 2
Dependent Claim
100 words
In a pressure sensitive instrument including a Bourdon tube operatively responsive to effect an output position change in correlation to changes in pressure from a source with which it is connected, the improvement in which said Bourdon tube is comprised of an iron chromium alloy obtained from a vacuum purification process and having a predominantly ferritic microstructure at room temperature consisting essentially of at least about 24 percent by weight chromium, at least about 1/2 percent by weight molybdenum, less than about 250 p.p.m. combined carbon plus nitrogen and the balance iron while being essentially free of volatile metallic impurities.
Claim 3
Dependent Claim
33 words
In a pressure sensitive instrument according to claim 1 in which said iron chromium alloy consists essentially of between about 24-28 percent by weight chromium and between about 1/2-2 percent by weight molybdenum.
Claim 4
Dependent Claim
19 words
In a pressure sensitive instrument according to claim 2 in which the pressure sensitive instrument comprises a pressure gauge.
Claim 5
Dependent Claim
31 words
In a pressure sensitive instrument according to claim 2 in which said iron chromium alloy consists essentially of about 26 percent by weight chromium and about 1 percent by weight molybdenum.
Claim 6
Dependent Claim
64 words
A Bourdon tube comprised of an iron chromium alloy obtained from a vacuum purification process and having a predominantly ferritic microstructure at room temperature consisting essentially of at least about 24 percent by weight chromium, at least about 1/2 percent by weight molybdenum, less than about 250 p.p.m. combined carbon plus nitrogen and the balance iron while being essentially free of volatile metallic impurities.
Claim 7
Dependent Claim
64 words
A Bourdon tube comprised of an iron chromium alloy obtained from a vacuum purification process and having a predominantly ferritic microstructure at room temperature consisting essentially of at least about 24 percent by weight chromium, at least about 1/2 percent by weight molybdenum, less than about 250 p.p.m. combined carbon plus nitrogen and the balance iron while being essentially free of volatile metallic impurities.
Claim 8
Dependent Claim
31 words
A Bourdon tube according to claim 5 in which said iron chromium alloy consists essentially of between about 24-28 percent by weight chromium and between about 1/2-2 percent by weight molybdenum.
Claim 9
Dependent Claim
29 words
A Bourdon tube according to claim 6 in which said iron chromium alloy consists essentially of about 26 percent by weight chromium and about 1 percent by weight molybdenum.
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) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |