Pressure sensor having metallic diaphragm seal mount

• US 6,715,356 B2
• Filed: 12/13/2000
• Issued: 04/06/2004
• Est. Priority Date: 02/22/2000
• Status: Expired due to Term

• Current Assignee: Endress+Hauser GmbH+Co (ENDRESS)
• Original Assignee: Endress+Hauser GmbH+Co (ENDRESS)
• Inventors: Uehlin, Thomas, Hegner, Frank, Drewes, Ulfert, Martin, Rainer, Flögel, Karl, Schmidt, Elke, Banholzer, Karlheinz, Gerst, Peter
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Mack, Corey D.
• Application Number:
  US09/734,739
• Publication Number:
  US 20010015105A1
• Time in Patent Office: 1,210 Days
• Field of Search: 737/15, 737/16, 737/17, 737/18, 737/23, 737/24
• US Class Current: 73/715
• CPC Class Codes: G01L 9/0075 using a ceramic diaphragm, e.g. alumina, fused quartz, glass

Abstract

A pressure sensor that is particularly suitable for the food industry and the measuring accuracy of which is stable over a long time, having a diaphragm seal with a separating diaphragm on which a pressure to be measured acts and having a ceramic measuring cell which is connected to the diaphragm seal exclusively by inorganic materials, is provided, in which sensor the separating diaphragm and all further sensor components coming into contact during measurement with a medium of which the pressure is to be measured are metallic.

Claims

1. An absolute-pressure sensor or relative-pressure sensor for sensing a pressure with respect to vacuum or with respect to ambient pressure, respectively, said absolute-pressure sensor or relative-pressure sensor, having:

a housing;

a diaphragm seal with a separating diaphragm on which a pressure to be measured acts;

an elongated tube; and

a ceramic measuring cell fixed in said housing by being mounted in the axial direction on said elongated tube, and through which said ceramic measuring cell is connected to said diaphragm seal, wherein;

said ceramic measuring cell is connected exclusively by inorganic materials to said diaphragm seal; and

said separating diaphragm and all sensor components coming into contact during measurement with a medium, the pressure of which is to be measured, are metallic.

2. The pressure sensor as defined in claim 1, further having:

An electromechanical transducer for registering a deflection of said measuring diaphragm depending on said pressure to be measured and a reference pressure, and for converting said deflection into an electrical output signal, wherein;

said ceramic measuring cell has an internal space and a measuring diaphragm which subdivides said internal space into a first chamber and a second chamber;

said first chamber is connected to said diaphragm seal by said elongated tube;

said first chamber, said elongated tube and said diaphragm seal are filled with a fluid, which transfers said pressure acting on said separating diaphragm to said measuring diaphragm; and

said reference pressure acts on said measuring diaphragm in said second chamber.

3. The pressure sensor as defined in claim 2, wherein:

said second chamber has an opening through which said reference pressure is introduced to said second chamber; and

said reference pressure is ambient.

4. The pressure sensor as defined in claim 2, wherein:

said second chamber is hermetically sealed; and

said reference pressure is an absolute pressure prevailing in said second chamber.

5. The pressure sensor as defined in claim 1, further having:

a holder, wherein;

said ceramic measuring cell is additionally enclosed in the radial direction in said holder, said holder providing a constraint against deflection in the radial direction of said measuring cell on said elongated tube.

6. The pressure sensor as defined in claim 5, wherein:

said holder has a body made of an elastomer filling an intermediate space between said ceramic measuring cell and said housing.