Ultra high pressure transducers

• US 6,577,224 B2
• Filed: 03/22/2001
• Issued: 06/10/2003
• Est. Priority Date: 03/22/2001
• Status: Active Grant

• Current Assignee: Kulite Semiconductor Products Inc
• Original Assignee: Kulite Semiconductor Products Inc
• Inventors: Kurtz, Anthony D.
• Primary Examiner(s): Easthom, Karl D.
• Application Number:
  US09/815,101
• Publication Number:
  US 20020135456A1
• Time in Patent Office: 810 Days
• Field of Search: 338/42, 737/15, 737/21
• US Class Current: 338/42
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: G01L 23/18 by resistance strain gauges
• CPC Class Codes: H01L 2224/48091 Arched
• 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

An oil filled pressure transducer of the type employing a metal diaphragm has a diaphragm of a greater thickness than a conventional diaphragm. The thick diaphragm exhibits and accommodates extremely large pressures and deflects to cause a lower pressure to be transmitted to the oil. Because of the large thickness of the metal diaphragm, the diaphragm dissipates a predetermined percentage of the applied pressure, whereas a corresponding fraction of the applied pressure is transmitted to the oil and hence to the silicon sensors. In this manner the diaphragm acts as a step-down transformer where a portion of the force or pressure applied to the diaphragm is transmitted to the pressure sensor. The pressure sensor receives a pressure which is a fraction of the applied pressure and the sensor is compensated to produce an output proportional to the actual pressure as applied to the thick diaphragm.

Claims

1. A fluid filled transducer for measuring pressures greater than 50,000 psi, having a housing with an internal hollow containing a pressure transducer and said hollow filled with a fluid medium and having a metal diaphragm covering said hollow and fluid, said metal diaphragm operative to receive an applied force for transmission to said fluid medium and therefore to said transducer, the improvement therewith of:

said metal diaphragm being of a thickness in the range of 5-15 times greater than a compliant diaphragm thickness for a known pressure, wherein said greater thickness is operable to dissipate a at least half of said applied force thereby indicating a lower force applied to said pressure transducer.

2. The transducer according to claim 1 wherein said fluid is oil.

3. The transducer according to claim 1 wherein said diaphragm is stainless steel.

4. A pressure transducer for a given high pressure range operation, comprising:

a housing having an internal hollow with a top opening and a pressure sensor mounted in said hollow operative to provide an output according to a received pressure,

a pressure transmitting fluid located in said hollow and covering said sensor,

a metal diaphragm covering said top opening of said housing and selected to have a thickness in the range of 5-15 times greater than a compliant diaphragm thickness used at said given high pressure range operation, wherein said greater diaphragm is operative to at least half of an applied high pressure thereto and to transmit to said sensor in said fluid a corresponding remaining fraction of said applied pressure.

5. The pressure transducer according to claim 4 wherein said fluid is oil.

6. The pressure transducer according to claim 4 wherein said sensor is a piezoresistive sensor.

7. The pressure transducer according to claim 4 wherein said pressure range is between 30,000 to 100,000 psi.

8. The pressure transducer according to claim 4 wherein said thickness of said diaphragm is at least ten times thicker than said complaint diaphragm.

9. The pressure transducer according to claim 4 wherein said housing and diaphragm are fabricated from stainless steel.

10. A method for measuring a high-pressure applied to a fluid filled transducer having

a housing with an internal hollow containing a pressure transducer therein, said hollow further filled with a fluid medium and having a metal diaphragm having thickness significantly greater than that of a substantially compliant diaphragm for a known pressure covering said hollow and fluid, comprising the steps of:

applying said high pressure force to said metal diaphragm,

dissipating a at least one half of said applied force through said greater diaphragm thickness; and

measuring a remaining pressure at said pressure transducer.

11. The method according to claim 10, wherein said greater diaphragm thickness is in the range of 5-15 times that of a compliant diaphragm.

12. The method according to claim 10 wherein said fluid is oil.

13. The method according to claim 10, wherein said transducer is a piezoresistive sensor.