Pressure sensor having metallic diaphragm seal joint

• US 6,848,318 B2
• Filed: 01/23/2004
• Issued: 02/01/2005
• Est. Priority Date: 02/22/2000
• Status: Expired due to Fees

• Current Assignee: Endress+Hauser GmbH+Co (ENDRESS)
• Original Assignee: Endress+Hauser GmbH+Co (ENDRESS)
• Inventors: Banholzer, Karlheinz, Gerst, Peter, Uehlin, Thomas, Hegner, Frank, Drewes, Ulfert, Martin, Rainer, Flögel, Karl, Schmidt, Elke
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Mack, Corey D.
• Application Number:
  US10/762,287
• Publication Number:
  US 20040149042A1
• Time in Patent Office: 375 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 inter alia for the food industry and the measuring accuracy of which is stable over a long time, having a diaphragm seal (3, 45) with a separating diaphragm (7, 53) on which a pressure (P) to be measured acts and having a ceramic measuring cell (9, 57) which is connected to the diaphragm seal (3, 45) exclusively by inorganic materials, is provided, in which sensor the separating diaphragm (7, 53) and all further sensor components coming into contact during measurement with a medium of which the pressure (P) is to be measured are metallic.

Claims

1. A pressure sensor, having

a housing, said housing defining a cavity;

a diaphragm seal, comprising

a diaphragm seal body, said diaphragm seal body being connected to said housing, said diaphragm seal body comprising a first surface facing said cavity, a second surface facing away from said cavity, and a passageway extending between said first surface and said second surface,

a separating diaphragm on which a pressure to be measured acts, said separating diaphragm being sealingly attached to said second surface;

a ceramic pressure measuring cell;

having a ceramic base body and a ceramic pressure measuring diaphragm; and

a metallic joint, wherein

said pressure measuring cell is sealingly fastened to said housing in said cavity by means of said metallic joint, the pressure measuring diaphragm being in fluid communication with said passageway.

2. The pressure sensor of claim 1, wherein:

said housing consists of a material which has a coefficient of thermal expansion which is approximately equal to the coefficient of thermal expansion of the ceramic material of the ceramic pressure measuring cell.

3. A pressure sensor, having

a housing, said housing defining a cavity;

a diaphragm seal, comprising

a diaphragm seal body, said diaphragm seal body being connected to said housing, said diaphragm seal body comprising a first surface facing said cavity, a second surface facing away from said cavity, and a passageway extending between said first surface and said second surface,

a separating diaphragm on which a pressure to be measured acts, said separating diaphragm being sealingly attached to said second surface;

a ceramic pressure measuring cell;

having a ceramic base body and a ceramic pressure measuring diaphragm; and

an insert, said insert being mounted in said cavity, wherein;

said pressure measuring cell is fastened to said insert, said insert surrounding said pressure measuring cell in a pot-like manner, and the pressure measuring diaphragm being in fluid communication with said passageway.