Apparatus for determining and/or monitoring a process variable

• US 9,395,226 B2
• Filed: 11/30/2007
• Issued: 07/19/2016
• Est. Priority Date: 12/20/2006
• Status: Active Grant

• Current Assignee: Endress GmbH & Co. KG.
• Original Assignee: Endress + Hauser GmbH + Company KG (Endress+Hauser AG)
• Inventors: Wernet, Armin, Dieterle, Roland
• Primary Examiner(s): Benitez-Rosario, Joshua
• Assistant Examiner(s): RHODES-VIVOUR, TEMILADE S
• Application Number:
  US12/448,355
• Publication Number:
  US 20100141285A1
• Time in Patent Office: 3,154 Days
• Field of Search: 324/126, 324/754.04, 324/754.24, 73/17.3, 733/04.C
• US Class Current: 1/1
• CPC Class Codes: C12Q 1/00 Measuring or testing processes involving enzymes, nucleic acids or microorganisms measuring or testing apparatus with condition measuring or sensing means, e.g. colony counters, C12M1/34; Compositions therefor; Processes of preparing such compositions
• CPC Class Codes: C12Q 2304/00 Chemical means of detecting microorganisms
• CPC Class Codes: G01F 23/24 by measuring variations of resistance of resistors due to contact with conductor fluid
• CPC Class Codes: G01F 23/26 by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
• CPC Class Codes: G01N 2201/00 Features of devices classified in G01N21/00

Abstract

An apparatus for determining and/or monitoring at least one process variable of a medium. The apparatus includes at least one probe unit and at least one electronics unit, which supplies the probe unit with an electrical, exciter signal and which receives from the probe unit an electrical, measurement signal. The invention includes, that the probe unit has at least one inner electrode and at least one outer electrode surrounding the inner electrode.

Claims

1. An apparatus for capacitive determining and/or monitoring at least one process variable of a medium in a container, comprising:

at least one probe unit; and

at least one electronics unit, which supplies said at least one probe unit with an electrical, exciter signal and which receives from said at least one probe unit an electrical, measurement signal, wherein;

said probe unit has at least one inner electrode and at least one outer electrode surrounding the inner electrode;

said at least one inner electrode and said at least one outer electrode are insulated electrically relative to one another and relative to the medium;

said at least one electronics unit is embodied in such a manner that it supplies said at least one inner electrode and said at least one outer electrode alternately with the exciter signal, and that it receives and evaluates the measurement signals associated with the individual supplyings of said at least one inner electrode and at least one said outer electrode.

2. The apparatus as claimed in claim 1, wherein:

said at least one inner electrode is embodied to be rod shaped or cable shaped.

3. The apparatus as claimed in claim 1, wherein:

said at least one outer electrode is embodied, at least sectionally, to be tubular.

4. The apparatus as claimed in claim 1, wherein:

said at least one outer electrode has equal wall thickness.

5. The apparatus as claimed in claim 1, wherein:

said at least one outer electrode is embodied in such a manner, that they coaxially surround said at least one inner electrode.

6. The apparatus as claimed in claim 1,

wherein:

said exciter signal is an alternating voltage.

7. The apparatus as claimed in claim 6, wherein:

said at least one electronics unit is embodied in such a manner, that it produces the exciter signal with the same frequency or different frequencies.

8. The apparatus as claimed in claim 1, wherein:

said at least one electronics unit is embodied in such a manner that it supplies said at least one inner electrode or said at least one outer electrode in a predeterminable sequence with the exciter signal; and

the measurement signal is tapped from the electrode supplied with the exciter signal.

9. The apparatus as claimed in claim 1, wherein:

said at least one inner electrode and said at least one outer electrode is are all supplied with said exciter signal and said measurement signal is receivable from all of said at least one inner electrode and said at least one outer electrode.

10. An apparatus for measuring at least one process variable of a medium in a container, comprising:

at least one probe unit; and

at least one electronics unit, which supplies said at least one probe unit with an exciter signal and which receives from said at least one probe unit a measurement signal, wherein;

said probe unit has at least one inner electrode and at least two outer electrodes surrounding the inner electrode, wherein said at least two outer electrodes are tubular;

said at least one inner electrode and said at least two outer electrodes are insulated electrically relative to the medium;

said at least one electronics unit is embodied in such a manner that it supplies said at least one inner electrode and said at least two outer electrodes alternately with the exciter signal; and

the measurement signal is tapped from the electrode supplied with the exciter signal.