US4572000A — Pressure sensor with a substantially flat overpre…

Claim 1

Independent Claim 249 words

A transducer for sensing a magnitude of a first pressure and having a first pressure chamber and a second pressure chamber for sensing at least the magnitude of the first pressure comprising: a housing; center stop means on the housing and having a substantially flat first face for providing a portion of the first pressure chamber and a substantially flat second face for providing a portion of the second pressure chamber, respectively. first sensor diaphragm means open and responsive to said first pressure supported on the center stop means for enclosing, with the first face, the first pressure chamber, said first diaphragm means having a substantially flat surface contacting the flat first face at a substantially unstressed condition; second sensor diaphragm means supported on the center stop means for enclosing, with the second face, the second pressure chamber; passageway means provided in the center stop means for fluidically coupling the first pressure chamber to the second pressure chamber such that when the magnitude of a first pressure exceeds a predetermined magnitude the first sensor diaphragm is supported by the first face of the center stop means; a filling of substantially noncompressible fluid in the passageway means and in both the first and second chambers to bow both the first and second sensing diaphragm means away from the respective first and second faces with substantially equal external pressures on the first and second diaphragm means; and sensing means for sensing the deflection of at least one of the diaphragm means.

Claim 2

Dependent Claim 249 words

A transducer for sensing a magnitude of a first pressure and having a first pressure chamber and a second pressure chamber for sensing at least the magnitude of the first pressure comprising: a housing; center stop means on the housing and having a substantially flat first face for providing a portion of the first pressure chamber and a substantially flat second face for providing a portion of the second pressure chamber, respectively. first sensor diaphragm means open and responsive to said first pressure supported on the center stop means for enclosing, with the first face, the first pressure chamber, said first diaphragm means having a substantially flat surface contacting the flat first face at a substantially unstressed condition; second sensor diaphragm means supported on the center stop means for enclosing, with the second face, the second pressure chamber; passageway means provided in the center stop means for fluidically coupling the first pressure chamber to the second pressure chamber such that when the magnitude of a first pressure exceeds a predetermined magnitude the first sensor diaphragm is supported by the first face of the center stop means; a filling of substantially noncompressible fluid in the passageway means and in both the first and second chambers to bow both the first and second sensing diaphragm means away from the respective first and second faces with substantially equal external pressures on the first and second diaphragm means; and sensing means for sensing the deflection of at least one of the diaphragm means.

Claim 3

Dependent Claim 39 words

A transducer according to claim 1 wherein the noncompressible fluid filling the passageway means and the first and second chamber is under a predetermined pressure selected as a function of the maximum expected pressure at the lowest expected temperature.

Claim 4

Dependent Claim 15 words

A transducer according to claim 2 further comprising a first sensor and a second sensor.

Claim 5

Dependent Claim 61 words

A transducer according to claim 2 wherein the transducer further comprises first isolator means interposed between the first sensor diaphragm and the first pressure and fluidically coupled thereto such that the first pressure causes deflection of the isolator means and such that responsive to such deflection the fluidic coupling causes the first sensor diaphragm to deflect responsive to said first pressure.

Claim 6

Dependent Claim 119 words

A transducer according to claim 1 further comprising first isolator chamber means and second isolator chamber means, each such chamber means being fluidically coupled respectively to the first sensor diaphragm means and the second sensor diaphragm means, the first isolator chamber means being responsive to the first pressure, and the second isolator chamber means responsive to the second pressure, the fluidic coupling from the first isolator chamber affecting the first sensor diaphragm means and the fluidic coupling from the second isolator chamber affecting the second sensor diaphragm means, and differentials in the pressures acting on the first and the second isolator chamber causing the first and second sensor diaphragm means to be displaced responsive to such differential in pressure.

Claim 7

Dependent Claim 40 words

A transducer according to claim 1 wherein the sensing means comprises a capacitor formed by an electrical conductive surface portion of the first face and second capacitor plate formed by an electrically conductive surface portion of the first diaphragm means.

Claim 8

Dependent Claim 54 words

A transducer according to claim 1 wherein the sensing means is a first capacitor formed by conducting surfaces of the first face and the first diaphragm means for measuring a first capacitance and a second capacitor formed by conducting surfaces of the second face and the second diaphragm means for measuring a second capacitance.

Claim 9

Dependent Claim 35 words

The transducer of claim 1 wherein the diaphragms are each formed with an annular rim around the edges thereof, the diaphragms being fastened to the stop means at a portion thereof aligned with the rims.

Claim 10

Dependent Claim 32 words

The transducer of claim 8 wherein the rims extend in direction away from the respective faces of the plate, the housing being fastened to the rim of at least the first diaphragm.

Claim 11

Dependent Claim 20 words

The transducer of claim 8 wherein the diaphragm is formed of a brittle nonmetal having properties substantially equivalent to silcon.

Claim 12

Dependent Claim 209 words

A pressure transducer comprising: a plate having oppositely facing generally flat surfaces and an outer peripheral edge portion; a first sensor diaphragm sealingly fastened at its edges to the edge portion of the plate and overlying one of the oppositely facing surfaces, the first diaphragm initially being configured to have a flat face which, when fastened to the plate is substantially contiguous with such one surface; a second diaphragm sealingly fastened at its edges to the edge portions of the plate on the opposite surface of the plate and overlying a fluid passageway defined in the plate said fluid passageway extending between the oppositely facing surfaces of the plate within the space defined by the edges of the first and second diaphragms; a filling of substantially noncompressible fluid filling the passageway and of volume to move both of the diaphragms away from their respective surfaces of the plate to form fluid filled chambers; a housing overlying the first diaphragm and including means to introduce a pressure to be sensed into the housing to tend to deflect the first diaphragm toward the plate which deflection is resisted by the second diaphragm through the incompressible fluid between the diaphragms; and means to permit sensing deflection of at least the first diaphragm.

Claim 13

Dependent Claim 209 words

A pressure transducer comprising: a plate having oppositely facing generally flat surfaces and an outer peripheral edge portion; a first sensor diaphragm sealingly fastened at its edges to the edge portion of the plate and overlying one of the oppositely facing surfaces, the first diaphragm initially being configured to have a flat face which, when fastened to the plate is substantially contiguous with such one surface; a second diaphragm sealingly fastened at its edges to the edge portions of the plate on the opposite surface of the plate and overlying a fluid passageway defined in the plate said fluid passageway extending between the oppositely facing surfaces of the plate within the space defined by the edges of the first and second diaphragms; a filling of substantially noncompressible fluid filling the passageway and of volume to move both of the diaphragms away from their respective surfaces of the plate to form fluid filled chambers; a housing overlying the first diaphragm and including means to introduce a pressure to be sensed into the housing to tend to deflect the first diaphragm toward the plate which deflection is resisted by the second diaphragm through the incompressible fluid between the diaphragms; and means to permit sensing deflection of at least the first diaphragm.

Claim 14

Dependent Claim 28 words

The transducer of claim 11 wherein at least the first diaphragm comprises a brittle material diaphragm having the flat face formed across one entire side of the diaphragm.

Claim 15

Dependent Claim 32 words

The transducer of claim 12, and a rim member around the peripheral edges of the first diaphragm, the first diaphragm being sealingly fastened to the plate at locations aligned with the rim.

Claim 16

Dependent Claim 25 words

The transducer of claim 13 wherein said rim is of substantially greater height in direction perpendicular to the diaphragm than the thickness of the diaphragm.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-02-24	1989-08-26	1990-02-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-02-24	1993-08-26	1994-02-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-02-24	1997-08-26	1998-02-25	$7700.00	Window Closed / Lapsed

Pressure sensor with a substantially flat overpressure stop for the measuring diaphragm

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