ISOLATOR SYSTEM FOR A PRESSURE TRANSMITTER

• US 20150082892A1
• Filed: 09/26/2013
• Published: 03/26/2015
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Hedtke, Robert C., Petersen, Eric
• Granted Patent: US 9,588,003 B2
• Time in Patent Office: Days
• US Class Current: 73/706
• CPC Class Codes: G01L 19/0046 using isolation membranes G01L13/026 and G01L19/0645 take precedence

Abstract

An isolator system for a pressure transmitter includes a port internal to the transmitter, a sensor tube, and a fill tube. The sensor tube is connected to the port to fluidly connect a passageway through a transmitter body to a pressure sensor. The sensor tube includes a first end disposed in the port. The first end has a first cross-sectional area. The fill tube is internal to the transmitter and connected to the port to fluidly connect to the passageway. The fill tube includes a second end disposed in the port. The second end of the fill tube has a second cross-sectional area that is less than the first cross-sectional area of the sensor tube.

Claims

1. An isolator system for a pressure transmitter, the system comprising:

a port internal to the transmitter;

a sensor tube connected to the port to fluidly connect a passageway through a transmitter body to a pressure sensor, the sensor tube including a first end disposed in the port, the first end having a first cross-sectional area; and

a fill tube internal to the transmitter, the fill tube connected to the port to fluidly connect to the passageway, the fill tube including a second end disposed in the port, the second end having a second cross-sectional area that is less than the first cross-sectional area of the sensor tube.

2. The system of claim 1, further comprising:

an isolator rim around a concavity in the transmitter body, the concavity is fluidly connected to the port internal to the transmitter through the passageway;

an isolator diaphragm including a diaphragm rim sealed to the isolator rim; and

isolator liquid filling the sensor tube, the fill tube, the passageway, and the concavity between the isolator diaphragm and the transmitter body;

the fill tube adapted to seal the isolator liquid within the transmitter.

3. The system of claim 1, wherein the first cross-sectional area is between 52% and 90% of the sum of the first cross-sectional area and the second cross-sectional area.

4. The system of claim 3, wherein the first cross-sectional area is between 60% and 80% of the sum of the first cross-sectional area and the second cross-sectional area.

5. The system of claim 4, wherein the first cross-sectional area is approximately 67% of the sum of the first cross-sectional area and the second cross-sectional area.

6. The system of claim 1, wherein the first end and the second end have cross-sectional shapes that are at least one of a “

D”

shape and a half-circle shape.

7. The system of claim 1, wherein the first end and the second end have cross-sectional shapes that are circular.

8. The system of claim 1, wherein the first end and the second end are brazed into the port.

9. A pressure transmitter comprising:

a transmitter body including an isolator rim around a concavity that is fluidly connected to a port internal to the transmitter by way of a passageway through the transmitter body;

an isolator diaphragm including a diaphragm rim sealed to the isolator rim;

a pressure sensor fluidly connected to the passageway by a sensor tube, the sensor tube including a first end disposed in the port;

a fill tube internal to the transmitter, the fill tube fluidly connected to the passageway and adapted to seal isolator liquid within the transmitter, the fill tube including a second end disposed in the port; and

isolator liquid within the sensor tube, the fill tube, the passageway, and the concavity between the isolator diaphragm and the transmitter body;

wherein the first end of the sensor tube has a first cross-sectional area, the second end of the fill tube has a second cross-sectional area, and the first cross-sectional area is greater than the second cross-sectional area.

10. The transmitter of claim 9, wherein the first cross-sectional area is between 52% and 90% of the sum of the first cross-sectional area and the second cross-sectional area.

11. The transmitter of claim 10, wherein the first cross-sectional area is between 60% and 80% of the sum of the first cross-sectional area and the second cross-sectional area.

12. The transmitter of claim 11, wherein the first cross-sectional area is approximately 67% of the sum of the first cross-sectional area and the second cross-sectional area.

13. The transmitter of claim 9, wherein the first end and the second end have cross-sectional shapes that are at least one of a “

D”

shape and a half-circle shape

14. The transmitter of claim 9, wherein the first end and the second end are brazed into the port.

15. The transmitter of claim 9, wherein the port is a raised boss.

16. The transmitter of claim 9, wherein the transmitter is a differential pressure transmitter and the pressure sensor is a differential pressure sensor including a second sensor tube and a second fill tube.

17. An isolator system for a pressure transmitter, the system comprising:

an isolator rim around a concavity in a transmitter body, the concavity fluidly connected to a port internal to the transmitter through a passageway through the transmitter body;

an isolator diaphragm including a diaphragm rim sealed to the isolator rim;

a sensor tube fluidly connecting the passageway to a pressure sensor;

a fill tube internal to the transmitter, the fill tube fluidly connected to the passageway; and

isolator liquid filling the sensor tube, the fill tube, the passageway, and the concavity between the isolator diaphragm and the transmitter body;

the fill tube adapted to seal the isolator liquid within the transmitter;

wherein the sensor tube includes a first end disposed in the port, the fill tube includes a second end disposed in the port, the first end of the sensor tube has a first cross-sectional area, the second end of the fill tube has a second cross-sectional area, and the first cross-sectional area is greater than the second cross-sectional area.

18. The system of claim 17, wherein the first end of the sensor tube and the second end of the fill tube have cross-sectional shapes that are at least one of a “

D”

shape and a half-circle shape.

19. The system of claim 17, wherein the first cross-sectional area is between 52% and 90% of the sum of the first cross-sectional area and the second cross-sectional area.

20. The system of claim 19, wherein the first cross-sectional area is between 60% and 80% of the sum of the first cross-sectional area and the second cross-sectional area.

21. The system of claim 20, wherein the first cross-sectional area is approximately 67% of the sum of the first cross-sectional area and the second cross-sectional area.