US5333504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High overpressure low range pressure sensor
Assignee: Rosemount Inc
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Filing: 1992-09-01
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Granted: 1994-08-02
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Expires: 2012-09-01
Abstract
Abstract A low range pressure sensor includes a base plate of brittle material, and a diaphragm plate mounted on the base plate and sealed around a periphery to the base plate. Pressures are introduced to cause the diaphragm to deflect toward the base plate, and the deflection of the diaphragm is sensed through strain gauges to provide an indication of the pressure. The diaphragm is provided with a plurality of individual support posts on a side facing the base plate, so that when the diaphragm is deflected toward the base plate under high overpressures the support posts will support the diaphragm against movement to avoid failure or breakage of the diaphragm. The number of support posts can be varied as desired. In a preferred form of the invention, the base plate is provided with a very thin layer of silicon dioxide, which is a good electrical insulator and which also serves to help accommodate slight movement of the support posts as they touch the surface of the base plate to reduce stress buildup in the diaphragm as the overpressure increases.
Inventors
- 👤 Mark A. Lutz
- 👤 William B. Krueger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:20
CPC Classifications
G; G01; G01L; G01L19/00; G01L19/06; G01L19/0618; G01L1/00; G01L1/20; G01L1/22; G01L9/00; G01L9/0041; G01L9/0042
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
95 words
A pressure sensor comprising a base plate, a diaphragm plate including a rim secured to the base plate, and a central diaphragm web section that is deflectable under force toward the base plate comprising; a plurality of posts formed on one of said plates in registry with the deflectable web section, and forming stops when the deflectable web section is deflected toward the base plate a preselected amount, said plurality of posts being integrally formed with said deflectable web section of said diaphragm and having ends which engage the base plate for forming the stops.
Claim 2
Dependent Claim
95 words
A pressure sensor comprising a base plate, a diaphragm plate including a rim secured to the base plate, and a central diaphragm web section that is deflectable under force toward the base plate comprising; a plurality of posts formed on one of said plates in registry with the deflectable web section, and forming stops when the deflectable web section is deflected toward the base plate a preselected amount, said plurality of posts being integrally formed with said deflectable web section of said diaphragm and having ends which engage the base plate for forming the stops.
Claim 3
Dependent Claim
37 words
The sensor of claim 1 wherein said posts have outer end surfaces that are substantially planar for contacting a facing surface of the base plate when the diaphragm is deflected a preselected amount toward the base plate.
Claim 4
Dependent Claim
44 words
The sensor of claim 2 and a layer of oxide formed on said base plate forming a shallow layer that is of a different material than the posts, to permit slight shifting of the ends of the posts as they contact the base plate.
Claim 5
Dependent Claim
22 words
The sensor of claim 3 wherein said base plate is made of silicon, and the shallow layer is formed of silicon dioxide.
Claim 6
Dependent Claim
14 words
The sensor of claim 4 wherein the silicon dioxide is substantially three microns thick.
Claim 7
Dependent Claim
47 words
The sensor of claim 5 wherein the base plate has a surface facing the posts, which is recessed a greater depth in the regions in registry with the central portions of the deflectable web section than at the edges of the base plate underlying the rim section.
Claim 8
Dependent Claim
20 words
The sensor of claim 1 wherein there is a plurality of at least four posts on the diaphragm web section.
Claim 9
Dependent Claim
82 words
A pressure sensor comprising a base plate, a diaphragm plate including a rim secured to the base plate, and a central diaphragm web section that is deflectable under force toward the base plate comprising; a plurality of posts formed on one of said plates in registry with the deflectable web section, and forming stops when the deflectable web section is deflected toward the base plate a preselected amount, the plurality of posts comprising at least four posts on the diaphragm web section.
Claim 10
Dependent Claim
82 words
A pressure sensor comprising a base plate, a diaphragm plate including a rim secured to the base plate, and a central diaphragm web section that is deflectable under force toward the base plate comprising; a plurality of posts formed on one of said plates in registry with the deflectable web section, and forming stops when the deflectable web section is deflected toward the base plate a preselected amount, the plurality of posts comprising at least four posts on the diaphragm web section.
Claim 11
Dependent Claim
17 words
The sensor of claim 8 wherein there are 16 posts evenly spaced on the diaphragm web section.
Claim 12
Dependent Claim
105 words
A pressure sensor comprising a base plate having a central portion, a diaphragm plate including a rim secured to the base plate, and a central diaphragm portion having a deflectable web section deflectable under force toward the base plate, comprising; a plurality of posts formed on one of said plates in registry with the deflectable web section, and forming stops when the deflectable web section is deflected toward the base plate a preselected amount; the plate other than the one plate having a surface facing the posts, which surface is recessed a greater depth in central portions of the other plate than at edges thereof.
Claim 13
Dependent Claim
105 words
A pressure sensor comprising a base plate having a central portion, a diaphragm plate including a rim secured to the base plate, and a central diaphragm portion having a deflectable web section deflectable under force toward the base plate, comprising; a plurality of posts formed on one of said plates in registry with the deflectable web section, and forming stops when the deflectable web section is deflected toward the base plate a preselected amount; the plate other than the one plate having a surface facing the posts, which surface is recessed a greater depth in central portions of the other plate than at edges thereof.
Claim 14
Dependent Claim
81 words
The sensor of claim 10 and wherein the posts are carried by the deflectable web section and the other plate is the base plate, the posts having ends which engage surface of the base plate, and a layer of oxide formed on the surface of the base plate forming a shallow layer that is not as hard as the base plate, to permit slight shifting of the ends of the posts as the posts contact the surface of the base plate.
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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) | 1997-08-01 | 1998-01-31 | 1998-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-01 | 2002-01-31 | 2002-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-01 | 2006-01-31 | 2006-08-02 | $7700.00 | Window Closed / Lapsed |