Capacitive based pressure sensor design

• US 6,029,525 A
• Filed: 02/04/1998
• Issued: 02/29/2000
• Est. Priority Date: 02/04/1998
• Status: Expired due to Term

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Grudzien, Christopher P.
• Primary Examiner(s): OEN, WILLIAM L
• Application Number:
  US09/018,395
• Time in Patent Office: 755 Days
• Field of Search: 73/715, 73/718, 73/724, 73/706, 73/714, 361/283.1, 361/283.3
• US Class Current: 73/718
• CPC Class Codes: G01L 9/0072 using variations in capacitance

Abstract

The disclosed pressure transducer assembly includes a first body, a second body, a diaphragm, and an electrode. The first body induces a case, one or more spokes, and a hub. The case has an interior surface. Each of said spokes extends from a first end to a second end. The first end of each spoke contacts the interior surface and the second end of each spoke contacts the hub. The diaphragm is mounted between the first and second bodies. The first body and the diaphragm form a first chamber. The second body and the diaphragm form a second chamber. A portion of the diaphragm flexes in a first direction in response to pressure in the first chamber being greater than pressure in the second chamber. A portion of the diaphragm flexes in a second direction, opposite the first direction, in response to pressure in the second chamber being greater than pressure in the first chamber. The electrode is disposed in the first chamber and is fixed to the hub. A capacitance between the electrode and the diaphragm is representative of a difference between the pressures in the first and second chambers.

Claims

1. A pressure transducer assembly comprising:

(A) a first body including a case, one or more spokes, and a hub, said case having an interior surface, each of said spokes extending from a first end to a second end, the first end of each spoke contacting said interior surface, the second end of each spoke contacting said hub;

(B) a second body;

(C) a diaphragm mounted between said first body and said second body, said first body and said diaphragm defining a first chamber, said second body and said diaphragm defining a second chamber, a portion of said diaphragm flexing in a first direction in response to a pressure in said first chamber being higher than a pressure in said second chamber, said portion of said diaphragm flexing in a second direction opposite said first direction in response to said pressure in said second chamber being higher than said pressure in said first chamber;

(D) an electrode disposed in said first chamber, said electrode being fixed to said hub, a capacitance between said electrode and said diaphragm being representative of a difference between said pressures in said first and second chambers.

2. An assembly according to claim 1, wherein said spokes define reentrant grooves.

3. An assembly according to claim 1, wherein said case, said spokes, and said hub are of a monolithic construction.

4. An assembly according to claim 1, wherein said electrode comprises an electrically insulative member and a conductor disposed on said electrically insulative member.

5. An assembly according to claim 1, further comprising a spacer disposed between said electrode and said hub.

6. A pressure transducer assembly comprising:

(A) a first body including a case, one or more spokes, and a hub, said case having an interior surface, each of said spokes extending from a first end to a second end, the first end of each spoke contacting said interior surface, the second end of each spoke contacting said hub;

(B) a second body;

(C) a diaphragm mounted between said first body and said second body, said first body and said diaphragm defining a first chamber, said second body and said diaphragm defining a second chamber, a portion of said diaphragm flexing in a first direction in response to a pressure in said first chamber being higher than a pressure in said second chamber, said portion of said diaphragm flexing in a second direction opposite said first direction in response to said pressure in said second chamber being higher than said pressure in said first chamber;

(D) an insulator disposed in said first chamber;

(E) a fastener fixing said insulator to said hub;

(F) a conductor disposed on said insulator, said conductor and said diaphragm being characterized by a capacitance, said capacitance being representative of a difference between said pressures in said first and second chambers.

7. An assembly according to claim 6, wherein said fastener comprises a screw.

8. An assembly according to claim 6, wherein said fastener comprises a rivet.

9. An assembly according to claim 6, wherein said fastener comprises an adhesive.

10. An assembly according to claim 6, wherein said hub and said fastener are metallic.

11. An assembly according to claim 10, wherein said fastener is welded to said hub.

12. A pressure transducer assembly comprising:

(A) a body having an interior surface and defining an interior cavity;

(B) a diaphragm mounted in said body and dividing said interior cavity into a first chamber and a second chamber, a portion of said diaphragm flexing in a first direction in response to a pressure in said first chamber being higher than a pressure in said second chamber, said portion of said diaphragm flexing in a second direction opposite said first direction in response to said pressure in said second chamber being higher than said pressure in said first chamber;

(C) a hub disposed in said first chamber;

(D) one or more spokes disposed in said first chamber, each of said spokes extending from a first end to a second end, said first end of each of said spokes contacting said interior surface, said second end of each of said spokes contacting said hub;

(D) an electrode disposed in said first chamber, said electrode being fixed to said hub, a capacitance between said electrode and said diaphragm being representative of a difference between said pressures in said first and second chambers.