Carrier assembly for fluid sensor

• US 5,763,787 A
• Filed: 09/05/1996
• Issued: 06/09/1998
• Est. Priority Date: 09/05/1996
• Status: Expired due to Term

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Johnson, Bruce L., Romo, Mark, Gravel, James L.
• Primary Examiner(s): Dombroske, George M.
• Assistant Examiner(s): FELBER, JOSEPH LEON
• Application Number:
  US08/711,408
• Time in Patent Office: 642 Days
• Field of Search: 137/487.5, 73/756, 73/721, 73/720
• US Class Current: 73/756
• CPC Class Codes: G01D 11/24 Housings ; Casings for instruments
• CPC Class Codes: G01L 19/0038 being part of the housing other details about the housing G01L19/14
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: G01L 19/142 Multiple part housings
• CPC Class Codes: G01L 19/143 Two part housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

A carrier assembly includes a sensor housing having first and second housing portions and a sensor cavity formed therebetween for carrying a sensor. A carrier assembly couples to the sensor and provides electrical connections which extend from the sensor and between the first and second housing. The sensor couples to a fluid and provides a sensor electrical output.

Claims

1. An apparatus used to measure a fluid parameter of a fluid, comprising:

a first fluid coupling having a first coupling passageway formed therethrough for carrying the fluid;

a sensor assembly having a first housing portion and a second housing portion forming a sensor cavity between respective first and second housing portion cavities, the sensor assembly including a housing passageway formed through one of the first housing portion and second housing portion for operably coupling the sensor cavity to the fluid coupling;

a sensor in the sensor cavity having a sensor electrical contact isolated from the fluid providing a sensor output related to the fluid parameter and suspended between the first and second housing portion cavities; and

a sensor carrier positioning the sensor in the sensor cavity and having an electrical conductor which couples to the sensor electrical contact and extends from the sensor cavity, the sensor carrier releasably coupled to the sensor.

2. The apparatus of claim 1 wherein the first housing portion and second housing portion are adapted to fit together.

3. The apparatus of claim 1 wherein the first housing portion and second housing portion have registration features that cooperate to register the sensor within the sensor cavity.

4. The apparatus of claim 1 wherein the sensor comprises a solid-state sensor.

5. The apparatus of claim 1 wherein the sensor comprises a pressure sensor.

6. The apparatus of claim 1 including a second fluid coupling having a second coupling passageway for carrying fluid and the sensor assembly includes a second housing passageway extending through the other of the first housing portion and second housing portion, the second housing passageway coupling the second coupling passageway to the sensor cavity.

7. The apparatus of claim 6 wherein the passageways are adapted to provide a flow of fluid through the sensor cavity.

8. The apparatus of claim 1 wherein the sensor measures a parameter selected from the group consisting of pH, temperature, flow rate, humidity, fluid electrical conductivity, heat capacity, fluid thermal conductivity, and fluid optical characteristics.

9. The apparatus of claim 6 wherein the sensor comprises a differential pressure sensor.

10. The apparatus of claim 1 wherein:

the first housing portion includes a sensor coupling face, and a first rim disposed on the sensor coupling face forming a first cavity therein which communicates with the housing passageway;

the second housing portion includes an interior face, and a second rim disposed on the interior face forming a second cavity therein which communicates with a second passageway; and

the sensor includes a first face, a second face opposed to the first face, and a sensing element therebetween, a first seal disposed on the first face about the sensing element coupled to the first rim couples the sensor to the housing passageway, and a second seal disposed on the second face about the sensing element coupled to the second rim couples the sensor to the second passageway.

11. The apparatus of claim 10 wherein the first and second seals comprise printed elastomeric material.

12. The apparatus of claim 1 wherein the sensor is mounted with substantially zero insertion force.

13. The apparatus of claim 1 wherein the sensor carrier includes two elongated arms adapted to receive the sensor therebetween.

14. The apparatus of claim 13 wherein the two arms include registration protrusions to thereby secure the sensor carrier in the sensor cavity between the first and second housing portions.

15. The apparatus of claim 1 including:

input circuitry for coupling to a process control loop;

a pressure input for coupling to a source of pressurized gas;

a pressure controller coupling to the pressure input and providing a control output adapted for controlling a valve in response to a control input, wherein the fluid coupling couples to the control output; and

a control circuit electrically coupled to the sensor electrical contact providing the control input to the pressure controller to thereby control the control output based upon an input received by the input circuitry from the process control loop and a pressure feedback signal provided by the sensor.

16. The apparatus of claim 1 wherein the fluid coupling is adapted for coupling to process fluid and further including:

transmitter circuitry coupled to the sensor electrical contact and a two-wire process control loop receiving the sensor output and responsively transmitting a transmitter signal related to the sensed fluid parameter over the two-wire process control loop.

17. The apparatus of claim 1 wherein the first and second housings include snap fit mounts which couple the first housing to the second housing.

18. The apparatus of claim 1 including an elastomeric conductor which forms an electrical contact with the sensor electrical contact and extends through an opening in the housing.

19. The apparatus of claim 18 including an external electrical contact mounted to the housing and wherein the elastomeric conductor provides an electrical contact between an external electrical contact and the sensor electrical contact.

20. The apparatus of claim 19 including a circuit board carrying the external electrical contact.

21. The apparatus of claim 1 including an opening formed in the housing for injecting a seal into the cavity which seals the sensor to the housing.