SENSOR DEVICE FOR CONDUCTIVITY MEASUREMENT AND METHOD FOR ITS OPERATION

• US 20090072835A1
• Filed: 11/24/2008
• Published: 03/19/2009
• Est. Priority Date: 05/24/2006
• Status: Active Grant

• Current Assignee: EGO Elektro-Gerã¤Tebau GmbH (EGO Blanc und Fischer & Company GmbH)
• Original Assignee: EGO Elektro-Gerã¤Tebau GmbH (EGO Blanc und Fischer & Company GmbH)
• Inventors: Schmidt, Kay, Munzner, Rainer, Dorwarth, Ralf
• Granted Patent: US 7,705,603 B2
• Time in Patent Office: Days
• US Class Current: 324/448
• CPC Class Codes: A47L 15/4297 Arrangements for detecting or measuring the condition of the washing water, e.g. turbidity
• CPC Class Codes: D06F 2103/16 Washing liquid temperature
• CPC Class Codes: D06F 2103/20 Washing liquid condition, e.g. turbidity
• CPC Class Codes: D06F 34/22 Condition of the washing liquid, e.g. turbidity
• CPC Class Codes: G01N 27/06 of a liquid involving electrolysis G01N27/26

Abstract

A sensor device for insertion into a water channel in a washing machine is provided with two electrodes as sensors on a sensor carrier. These electrodes are in direct contact with the water through apertures. The electrodes are connected to a transformer on the sensor carrier directly and without any further components or couplings being required. The other side of the transformer is connected to an activating and evaluating means, in particular to a microprocessor positioned on the same carrier.

Claims

1. A sensor device for conductivity measurement for an electrical appliance having a water duct with contaminated water, wherein said sensor device has a sensor carrier, said sensor carrier having two electrodes as sensors for said conductivity measurement, wherein said two electrodes are connected directly without further components or further coupling circuits to a transformer configured to be connected to a control unit.

2. The sensor device according to claim 1, wherein said transformer is positioned on said sensor carrier with a spacing between one of said electrodes wherein said spacing is of the same order of magnitude as the spacing between said two electrodes.

3. The sensor device according to claim 2, wherein the transformer is positioned in said sensor device with a spacing of a few centimetres of said electrodes.

4. The sensor device according to claim 1, wherein said electrodes and said trans-former form a common module on a common printed circuit board comprising electrical connections in the form of conducting tracks on said printed circuit board between said electrodes and said transformer.

5. The sensor device according to claim 1, comprising an elongated or channel-like sensor housing wherein in the ready-to-operate state said electrodes are configured to be at least partly exposed to said contaminated water.

6. The sensor device according to claim 1, wherein said electrodes and said trans-former are located in an interior of a sensor housing, an electrical connection provided for an electrical connection to an end projecting from a rear of said sensor housing of a common printed circuit board for said electrodes and said transformer.

7. The sensor device according to claim 6, wherein said sensor housing has a tubular shape with one end comprising a flattened area and apertures therein and on which are located said electrodes.

8. The sensor device according to claim 7, wherein said electrodes are sealed against said apertures.

9. The sensor device according to claim 6, wherein a bus connection is provided between said transformer and said electrical connection as an interface for activating or evaluating said sensors.

10. The sensor device according to claim 1, wherein an electrical connection is located that is configured to be outside water-contacting areas of said electrical appliance.

11. The sensor device according to claim 1, wherein on a common printed circuit board for said electrodes and said transformer, a microprocessor and its wiring is provided, wherein an electrical connection for said microprocessor is located outside a sensor housing of said sensor device.

12. The sensor device according to claim 1, wherein further sensors are provided on or in a sensor housing and are exposed to outside of said sensor housing.

13. The sensor device according to claim 12, wherein one said further sensor at high frequencies of an activation means has a high-impedance and at low frequencies has a low-impedance.

14. The sensor device according to claim 12, wherein one of said further sensors gives rise to a damping to be evaluated on said activation means or said transformer.

15. The sensor device according to claim 12, wherein at least one said sensors has a frequency dependency for activation and one other said sensor is frequency-independent for separately measuring values of said other sensor.

16. The sensor device according to claim 12, wherein at least one of said sensors has a resonant frequency for an evaluation of said sensor, wherein said at least one of said sensors has a lower impedance than other frequencies in a remaining frequency range.

17. A method of operating a sensor device for an electrical appliance having a water duct with contaminated water, wherein said sensor device has a sensor carrier, said sensor carrier having two electrodes as sensors for said conductivity measurement, wherein said two electrodes are connected directly without further components or further coupling circuits to a transformer configured to be connected to a control unit, comprising the steps of:

activating said electrodes using a transformer with a plurality of high frequency pulses for measuring a damping of said high frequency pulses at said electrodes through a conductance of said water.