Media compatible pressure sensor

• US 6,311,561 B1
• Filed: 02/01/1999
• Issued: 11/06/2001
• Est. Priority Date: 12/22/1997
• Status: Expired due to Fees

• Current Assignee: Rosemount Aerospace, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rosemount Aerospace, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Nagy, Michael L., Yang, Xiaofeng, Bang, Christopher A., Just, Marcus S.
• Primary Examiner(s): OEN, WILLIAM L
• Application Number:
  US09/241,273
• Time in Patent Office: 1,009 Days
• Field of Search: 737/15, 737/16, 737/17, 737/18, 737/19, 737/20, 737/21, 737/22, 737/23, 737/24, 737/25, 737/26, 737/27, 737/06, 737/56
• US Class Current: 73/708
• 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 19/143 Two part housings
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A media compatible package for a pressure sensing device is made from a non-corrosive, highly chemical resistant material. The package includes a base which holds a printed circuit board having a pressure sensor mounted thereon. A sealing member is placed on the circuit board encircling the pressure sensor and a diaphragm is disposed on the sealing member. A fluid port is attached to the base and compressingly engages the diaphragm creating a sealed chamber around the pressure sensor. The sealed chamber is filled with a pressure transmissive fluid such as oil through a fill hole provided in the printed circuit board. This configuration allows the sensor package to be easily assembled with ordinary components and provides a design where all exposed surfaces of the package can be made from a highly corrosion resistive material.

Claims

1. A pressure sensing device comprising:

a housing defining a fluid channel therethrough;

a circuit board mounted within the fluid channel;

a pressure sensor attached to the circuit board, the pressure sensor generating a signal in response to a pressure sensed thereon and communicating the signal to the circuit board;

a sealing member disposed on the circuit board and enclosing the pressure sensor;

a diaphragm disposed on the sealing member defining an enclosed chamber between the diaphragm and the circuit board, the pressure sensor being within the enclosed chamber, and the diaphragm being positioned having one surface in the fluid channel;

a pressure transmissive fluid filling the enclosed chamber such that a pressure applied to the diaphragm is transmitted by the pressure transmissive fluid and sensed by the pressure sensor; and

the circuit board, the sealing member and the diaphragm being compressively held together within the housing such that the enclosed chamber is sealed.

2. The pressure sensing device as set forth in claim 1 wherein the housing includes a first member and second member which attach together to form the housing, the attachment of the first and second members securing the circuit board, the sealing member and the diaphragm compressively together.

3. The pressure sensing device as set forth in claim 2 wherein the first and second members of the housing each include a threaded portion such that the first and second members screw together.

4. The pressure sensing device as set forth in claim 3 further including at least one pin for securing the first and second members together to prevent disassembly.

6. The pressure sensing device as set forth in claim 1 wherein the circuit board provides electrical communication from the pressure sensor to an exterior of the housing.

7. The pressure sensing device as set forth in claim 1 wherein the housing and the diaphragm are made of a plastic.

8. The pressure sensing device as set forth in claim 7 wherein the plastic is teflon.

9. The pressure sensing device as set forth in claim 1 wherein the housing includes a flush mount configuration.

5. The pressure sensing device as set forth in claim I further including a fill hole defined through the circuit board such that the enclosed chamber is filled with the pressure transmissive fluid through the fill hole.

10. A pressure sensing package for measuring pressure of a medium comprising:

a pressure sensing device including;

a circuit board;

a pressure sensor attached to and electrically connected to the circuit board;

a sealing member disposed on the circuit board and surrounding the pressure sensor;

a diaphragm disposed on the sealing member and covering the pressure sensor such that a chamber is defined by the diaphragm, the sealing member and the circuit board; and

a pressure transmissive fluid filled in the chamber such that a pressure exerted on the diaphragm is transmitted through the pressure transmissive fluid and sensed by the pressure sensor; and

a housing having a channel defined therein which allows a medium to flow into the housing, the pressure sensing device being mounted within the channel of the housing such that only the diaphragm is exposed to contact the medium, the pressure sensing device being compressively held together by the housing.

11. The pressure sensing package as set forth in claim 10 wherein the housing includes a base and a fluid port where the pressure sensing device is mounted within the base and the fluid port attaches to the base to secure the pressure sensing device by compression.

12. The pressure sensing package as set forth in claim 11 wherein the base includes a threaded portion and the fluid port includes a threaded portion, the base and fluid port being attached by screwing together.

13. The pressure sensing package as set forth in claim 12 wherein the base and the fluid port are secured together to prevent unthreading.

14. The pressure sensing package as set forth in claim 10 wherein the circuit board includes a fill hole defined therethrough where the pressure transmissive fluid is passed through the fill hole to fill the chamber.

15. The pressure sensing package as set forth in claim 14 wherein circuit board further includes a sealing member for sealing the fill hole.

16. The pressure sensing package as set forth in claim 10 wherein the circuit board includes a vent hole such that pressure sensed by the pressure sensor is measured relative to ambient.

17. The pressure sensing package as set forth in claim 10 wherein the chamber has a volume which is decreased by compression of the sealing member against the diaphragm and the circuit board.

18. The pressure sensing package as set forth in claim 10 wherein the sealing member is a resilient O-ring.

19. The pressure sensing package as set forth in claim 10 wherein the housing is a flush mount housing.

20. A pressure sensing device comprising:

a housing having an inner cavity;

a circuit board mounted in said inner cavity;

a pressure sensor coupled to said circuit board, said pressure sensor generating an output signal in response to a sensed pressure and communicating said signal to said circuit board;

a sealing member disposed on said circuit board and receiving said pressure sensor therein; and

a diaphragm disposed on said sealing member, wherein said circuit board, said sealing member and said diaphragm define an enclosed chamber, said pressure sensor being located in said enclosed chamber, and wherein said enclosed chamber can receive a pressure transmissive fluid such that a pressure applied to said diaphragm is transmitted by said pressure transmissive fluid and sensed by said pressure sensor.