Apparatus for conveying fluid pressures to a differential pressure transducer

• US 4,466,290 A
• Filed: 11/27/1981
• Issued: 08/21/1984
• Est. Priority Date: 11/27/1981
• Status: Expired due to Term

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Frick, Roger L.
• Primary Examiner(s): WOODIEL, DONALD
• Application Number:
  US06/325,342
• Time in Patent Office: 998 Days
• Field of Search: 73/756, 73/716-722, 73/706, 73/861.47, 73/861.48, 285/137 R, 361/283, 137/594
• US Class Current: 73/756
• CPC Class Codes: G01L 13/025 using diaphragms
• CPC Class Codes: G01L 19/0038 being part of the housing other details about the housing G01L19/14
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: G01L 19/142 Multiple part housings
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• CPC Class Codes: G01L 27/002 Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination

Abstract

An improved apparatus for conveying fluid pressures to a differential pressure transducer is disclosed. The apparatus comprises a single flange connected to and fluidly coupled to the differential pressure transducer for conveying the fluid pressures thereto. A further improvement comprises incorporating a three valve manifold integral to the single flange for controlling the fluid pressure to the differential pressure transducer.

Claims

1. A differential pressure transducer having a single coupling body defining body face surface means;

separate first and second pressure inlets extending through the coupling body from a differential pressure sensor element and both inlets opening through the face surface means;

first and second flexible isolation diaphragm means overlying the openings of the respective first and second inlets and being sealed to the coupling body at rim portions surrounding the openings of the inlets, respectively, to isolate the inlets from external fluids, the isolation diaphragms both facing in the same direction outwardly from the coupling body for receiving fluid under pressure from first and second sources of fluid, the difference in pressure of which is to be measured;

a flange for carrying fluid pressure from such sources to the isolation diaphragms comprising a single massive body having first and second faces;

first and second fluid passageways defined through the flange, each such passageway extending from the first face to the second face, the flange including means for coupling the first ends of the passageways to first and second sources of fluid under pressure, second ends of the passageways opening to the second face of the flange at separate locations, the flange being configured so the second face is complementary in configuration to the body face surface means and sealingly mates with the face surface means of the coupling body of the differential pressure transducer to simultaneously couple each passageway in the flange to a respective isolation diaphragm;

means to convey fluid pressures acting on the isolation diaphragms to an associated differential pressure sensor element;

each such fluid passageway being adapted to separately convey fluid under pressure to one of the isolation diaphragms of the differential pressure transducer when the flange passageways are connected to sources of fluid under pressure to be measured.

2. A transducer as claimed in claim 1 wherein the flange is substantially an I-shaped, massive body having a first end member and a second end member, which members are joined by a center member, and including a first face defined on the first end member and a second face defined on the second end member, the first and second passageways extending between the first and second faces.

3. A differential pressure transmitter as claimed in claim 2 wherein the second face of the flange has first and second sealing portions formed therein annular to the second ends of the first and second fluid passageways, respectively, for effecting a substantially fluid tight seal in cooperation with flexible isolation diaphragms of a differential pressure transducer when the flange is connected thereto.

4. A differential pressure transmitter as claimed in claim 3 wherein the first and second sealing portions are substantially co-planar, and are adapted to mate with a surface of a differential pressure sensor.

5. A differential pressure transmitter as claimed in claim 4 wherein the first and the second sealing portions each are additionally comprised of sealing ring means and groove means, the groove means defined in the respective sealing portion for supporting the sealing ring means, the sealing ring means being supported in the groove means and held in compression by a differential pressure transducer to which the flange is mounted to further effect a substantially fluid tight seal around the respective fluid passageway.

6. The transducer of claim 1 and further comprising:

separate first and second valve means in the flange for controlling transfer of fluid pressures through each of the first and second passageways defined through the flange; and

third valve means in the flange operable for controlling fluid flow between the first and second passageways in the flange.

7. In combination with a differential pressure transmitter having differential pressure transducer means, an input/output means coupled to the differential pressure transducer means for powering the transducer means and for receiving an output signal therefrom, the differential transducer comprising sensor element means having portions for sensing the differential in pressure between the pressures of two fluids under pressure and for generating an output signal representative of such differential pressure, first and second signal transmission means communicatively connected to the sensor element means, each for communicating a response signal representative of a fluid pressure separately to the sensor element means;

first and second isolation diaphragm means communicatively connected to the first and second signal transmission means, respectively, the first and second isolation diaphragm means each having a rim defining a plane, and first surfaces oriented to be acted upon by the fluid under pressure to be sensed, respectively, and fluidly isolating the sensor element means from the fluid acting on the first surfaces, each isolation diaphragm means tending to deflect in response to fluid pressures acting thereon and any such deflection being communicated to the first and second signal transmission means, respectively, for transmission of signals representing such deflection to the sensor element means for generation of an output signal representative of the differential in the fluid pressures acting on the first and second isolation diaphragm means, which output signal is communicated to the input/output means, the improvement of a single flange means comprising a massive body having first and second faces, the first face of the flange means being adapted to be coupled separately to first and second inlet piping means carrying the first and second fluids under pressure, the pressure of which is to be sensed, the second face of the flange means having sealing portions configured for effecting a fluid seal between each isolation diaphragm means rim and the flange means, the plane of each isolation diaphragm means rim and the associated sealing portion being substantially parallel to each other, said flange means having first and second fluid passageway means defined therethrough, each such passageway means having a first end at the first face for coupling to one of the first and second inlet piping means, respectively, and a second end opening separately at the second face and being fluidly coupled to one of the first and second isolation diaphragm means within the area defined by the respective rim, each such fluid passageway means separately conveying fluid under pressure from a connected inlet piping means to the first surface of an associated isolation diaphragm means.

8. A differential pressure transmitter as claimed in claim 7 wherein the planes defined by the rims of the first and second isolation diaphragm means are co-planar with respect to one another.

9. A differential pressure transmitter as claimed in claim 8 wherein seal means are imposed between the flange means and the differential pressure transducer means annular to the first and second isolation diaphragm means for effecting a substantially fluid-tight seal.

10. A differential pressure transmitter as claimed in claim 9 wherein grooves are formed in the flange means means annular to the second end of both the first and second fluid passageway means and an o-ring is positioned in grooves for compression therein when the flange means is mated to the transducer means.

11. A differential pressure transmitter as claimed in claim 10 wherein the sensor element means is a capacitive type sensor.

12. In combination with a differential pressure transmitter having differential pressure transducer means, an input/output means coupled to the differential pressure transducer means for powering the transducer means and for receiving an output signal therefrom, the differential pressure transducer comprising sensor element means having portions for sensing the differential in pressure between the pressures of two fluids under pressure and for generating an output signal representative of such differential pressure, first and second signal transmission means communicatively connected to the sensor element means, each for communicating a response signal representative of a fluid pressure separately to the sensor element means;

first and second isolation diaphragm means communicatively connected to the first and second signal transmission means, respectively, the first and second isolation diaphragm means each having a rim defining a plane and first surfaces oriented to be acted upon by the fluid under pressure to be sensed, respectively, and fluidly isolating the sensor element means from the fluid acting on the first surfaces, each isolation diaphragm means tending to deflect in response to fluid pressures acting thereon and any such deflection being communicated to the first and second signal transmission means, respectively, for transmission of signals representing such deflection to the sensor element means for generation of an output signal representative of the differential in the fluid pressures on the first and second isolation diaphragm means, which output signal is communicated to the input/output means, a single flange means comprising a massive body having first and second faces, the second face of the flange means being configured for mating to the differential pressure transducer, said flange means having first and second passageway means defined therethrough extending between said first and second faces, each such passageway having a first end adapted to be coupled to the first and second inlet piping means, respectively, and a second end opening separately at the second face, the second face having sealing portions configured for effecting a seal between each isolation diaphragm means rim and the flange means, the plane of each isolation diaphragm means rim and the associated sealing portion being substantially parallel to each other, the second ends of the passageways at the second face being fluidly coupled to one of the first and second isolation diaphragm means within the area defined by the respective isolation diaphragm means rim, said flange means further having a cross connect passageway defined therein extending between and intersecting the first and second fluid passageways means for fluidly connecting the first and second fluid passageway means to each other, first valve means mounted in the first fluid passageway means, second valve means mounted in the second fluid passageway means, each such first and second valve means being located in the respective fluid passageway means between the intersection of the cross connect passageway means with the respective first and second passageway means and the means for connecting to the respective inlet piping means, said first and second valve means being operable for selectively admitting and excluding fluid under pressure conveyed from a connected inlet piping means, and a third valve means mounted in the cross connect passageway means for selectively fluidly connecting the first and second passageway means to each other.

13. A differential pressure transmitter as claimed in claim 12 wherein the planes defined by the rims of the first and second isolation diaphragm means are co-planar with respect to one another.

14. A differential pressure transmitter as claimed in claim 13 wherein seal means are imposed between the flange means and the differential pressure transducer means annular to the first and second isolation diaphragm means for further effecting a substantially fluid-tight seal.

15. A differential pressure transmitter as claimed in claim 14 wherein grooves are formed in the flange means annular to the second end of both the first and second fluid passageway means and an o-ring is positioned in grooves for compression therein when the flange means is mated to the transducer means.

16. A differential pressure transmitter as claimed in claim 15 wherein the sensor element means is a capacitive type sensor.