Flush-diaphragm relative pressure sensor

US6422085B1 · kind B1 · utility

Assignee

• Endress+Hauser Inc. · DE

Inventors

• Frank Hegner · Bad Kötzting, DE
• Andreas Rossberg · Bad Säckingen, DE
• Ulfert Drewes · Bad Hersfeld, DE
• Elke Schmidt · Bad Säckingen, DE

Key dates

• Filing date: Jul 16, 1999
• Grant date: Jul 23, 2002
• Expiry date: Jul 16, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L19/0636
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In this flush-diaphragm relative pressure sensor (1), the reference air reaches its current dew point before getting into the interior of the housing. The sensor has a capacitive, resistive, or piezoelectric sensing element (2) with a diaphragm (21) an external surface of which comes into direct contact with a medium under pressure. A housing (7) has an interior space (71) and a front portion (72) open across the interior space in the vicinity of which the diaphragm closes the interior space such that the front portion projects beyond the diaphragm. Further, the housing has a bore (721) extending through the front portion from an outer side thereof to the interior space for guiding the reference air. The bore is closed from the outer side with an open-pore, highly heat-conducting and hydrophobic filter (8), so that the filter and the diaphragm are at the same or nearly the same temperature. The filter can be made of a sintered metal, e.g. high-grade steel or bronze, or of a metallic sponge, e.g. titanium or zirconium.