Process fluid pressure transmitter with separated sensor and sensor electronics

• US 8,578,783 B2
• Filed: 09/26/2011
• Issued: 11/12/2013
• Est. Priority Date: 09/26/2011
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Hedtke, Robert C., Schulte, John, Broden, David A.
• Primary Examiner(s): ALLEN, ANDRE J
• Application Number:
  US13/245,306
• Publication Number:
  US 20130074604A1
• Time in Patent Office: 778 Days
• Field of Search: 73700-756
• US Class Current: 73/753
• CPC Class Codes: G01F 1/34 by measuring pressure or differential pressure
• CPC Class Codes: G01F 1/36 the pressure or differential pressure being created by the use of flow constriction
• CPC Class Codes: G01F 1/38 the pressure or differential pressure being measured by means of a movable element, e.g. diaphragm, piston, Bourdon tube or flexible capsule
• CPC Class Codes: G01F 1/42 Orifices or nozzles
• CPC Class Codes: G01F 15/06 Indicating or recording devices
• CPC Class Codes: G01F 15/061 for remote indication
• CPC Class Codes: G01L 19/0046 using isolation membranes G01L13/026 and G01L19/0645 take precedence
• CPC Class Codes: G01L 19/0061 Electrical connection means
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/0681 Protection against excessive heat
• CPC Class Codes: G01L 19/08 Means for indicating or recording, e.g. for remote indication

Abstract

A process fluid pressure transmitter has a remote pressure sensor. The transmitter includes an electronics housing and a loop communicator disposed in the electronics housing and being configured to communicate in accordance with a process communication protocol. A controller is disposed within the electronics housing and is coupled to the loop communicator. Sensor measurement circuitry is disposed within the electronics housing and is coupled to the controller. A remote pressure sensor housing is configured to couple directly to a process and is spaced from the electronics housing. A pressure sensor is disposed within the remote pressure sensor housing. The pressure sensor forms at least one electrical component having an electrical characteristic that varies with process fluid pressure. Portions of the electrical component are coupled directly to a multiconductor cable that operably connects the pressure sensor to the sensor measurement circuitry.

Claims

1. A process fluid pressure transmitter having a remote pressure sensor, the transmitter comprising:

an electronics housing;

a loop communicator disposed in the electronics housing and being configured to communicate in accordance with a process communication protocol;

a controller disposed within the electronics housing and coupled to the loop communicator;

sensor measurement circuitry disposed within the electronics housing and coupled to the controller;

a remote pressure sensor housing configured to couple adjacent to a process and being spaced from the electronics housing;

a pressure sensor disposed within the remote pressure sensor housing, the pressure sensor forming at least one electrical component having an electrical characteristic that varies with process fluid pressure; and

wherein portions of the electrical component are coupled directly to a multiconductor cable that operably connects the pressure sensor to the sensor measurement circuitry.

2. The process fluid pressure transmitter of claim 1, wherein the electrical component comprises at least one capacitor, and wherein each portion of the electrical component is a capacitive plate.

3. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing includes at least one isolation diaphragm isolating process fluid from the pressure sensor, but conveying process fluid pressure to the pressure sensor.

4. The process fluid pressure transmitter of claim 3, wherein the process fluid pressure is conveyed through a substantially incompressible fill fluid.

5. The process fluid pressure transmitter of claim 4, wherein the fill fluid is a single component silicone diffusion pump fluid.

6. The process fluid pressure transmitter of claim 1, wherein the pressure sensor is disposed to directly contact process fluid.

7. The process fluid pressure transmitter of claim 1, wherein the pressure sensor housing and electronics housing are coupled together with a rigid mount.

8. The process fluid pressure transmitter of claim 1, wherein the multiconductor cable is a shielded multiconductor cable.

9. The process fluid pressure transmitter of claim 1, and further comprising a temperature sensor disposed in the remote pressure sensor housing and being configured to measure process fluid temperature and provide an indication thereof to the sensor circuitry through the multiconductor cable.

10. The process fluid pressure transmitter of claim 9, wherein the controller is configured to compensate for thermal effects.

11. The process fluid pressure transmitter of claim 9, wherein the pressure sensor and the temperature sensor comprise the only electrical components within the pressure sensor housing.

12. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing is filled with a potting compound.

13. The process fluid pressure transmitter of claim 1, and further comprising:

a second remote pressure sensor housing configured to couple directly to a process;

a second pressure sensor disposed within the second remote pressure sensor housing, the second pressure sensor forming at least one electrical component having an electrical characteristic that varies with process fluid pressure; and

wherein portions of the electrical component are coupled directly to a multiconductor cable that operably connects the second pressure sensor to the sensor measurement circuitry.

14. The process fluid pressure transmitter of claim 1, wherein the pressure sensor comprises the only electrical component within the pressure sensor housing.

15. The process fluid pressure transmitter of claim 1, wherein the transmitter is configured to measure one of differential, gage, and absolute process fluid pressures.

16. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing is integrated into a process flow primary element.

17. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing is integrated into a remote process seal.

18. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing is integrated into a process vessel.

19. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing is integrated into a flow measurement device.

20. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing is coupled to the process in a coplanar pattern.

21. The process fluid pressure transmitter of claim 1, wherein the remote pressure sensor housing is modular.

22. The process fluid pressure transmitter of claim 1, and further comprising an intrinsic safety barrier disposed within the electronics housing and electrically interposed between the sensor electronics circuitry and the multiconductor cable.