Device for measuring a volume flow with inductive coupling

• US 20060191354A1
• Filed: 02/13/2006
• Published: 08/31/2006
• Est. Priority Date: 02/25/2005
• Status: Active Grant

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Drager Medical AG & Co KG (Dragerwerk AG)
• Inventors: Schulz, Volkmar, Gerder, Henning
• Granted Patent: US 7,418,859 B2
• Time in Patent Office: Days
• US Class Current: 73/861.08
• CPC Class Codes: A61M 16/0875 Connecting tubes
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: G01F 1/68 by using thermal effects
• CPC Class Codes: G01F 15/063 using electrical means

Abstract

A device for measuring a volume flow, especially a tidal volume flow sensor, with a flow channel (1) and with a sensor element (6) arranged within the flow channel (1), is shown and described. The task of providing such a device, in which the sensor signal, which is generated by sensor elements arranged in the flow channel, remains as free as possible from distortions during the transmission to an evaluating unit, is accomplished by providing an internal circuit (3), which is arranged within the flow channel (1) and includes the sensor element (6). An external circuit (7) is arranged outside the flow channel (1). The external circuit (7) is designed for contactless, inductive coupling with the internal circuit (3) for supplying same with energy and for reading.

Claims

1. A device for measuring a volume flow, the device comprising:

a flow channel;

a sensor element comprising an internal circuit arranged within said flow channel;

an external circuit arranged outside said flow channel, said external circuit providing contactless inductive coupling with said internal circuit for supplying said internal circuit with energy and for sensor reading including detecting operation of said internal circuit, corresponding to fluid flow in said flow channel.

2. A device in accordance with claim 1, wherein said sensor element comprises a hot wire having a temperature-dependent resistance.

3. A device in accordance with claim 1, wherein said internal circuit has a first inductive element and a first capacitive element.

4. A device in accordance with claim 3, wherein said capacitive element is a variable capacitance element providing a moisture sensor.

5. A device in accordance with claim 1, further comprising an internal temperature-measuring circuit with a temperature sensor element, said internal temperature-measuring circuit being provided in said flow channel.

6. A device in accordance with claim 5, wherein said temperature sensor element is designed as a resistance wire.

7. A device in accordance with claim 5, wherein said internal temperature-measuring circuit provides contactless, inductive coupling with said external circuit for said sensor reading.

8. A device in accordance with claim 5, further comprising an external temperature-measuring circuit for contactless, inductive coupling with said internal temperature-measuring circuit for sensor reading of said internal temperature-measuring circuit.

9. A device in accordance with one of the claims 5, wherein said internal temperature-measuring circuit has an internal temperature-measuring circuit inductive element and an internal temperature-measuring circuit capacitive element.

10. A device in accordance with claim 9, wherein said second capacitive element is designed as a variable element to provide a moisture sensor.

11. A device in accordance with claim 1, further comprising;

a heating element arranged in said flow channel;

a flow resistance arranged in said flow channel between said heating element and said internal circuit, said heating element and said flow resistance being arranged in a same cross sectional area of said flow channel.

12. A device in accordance with claim 11, wherein said flow resistance is designed as a projection in the wall of said flow channel.

13. A device in accordance with claim 11, wherein said cross sectional area of said flow channel heating element and said flow resistance is arranged centrally in said flow channel.

14. A device in accordance with claim 13, wherein said sensor element comprises a central web.

15. A device in accordance with claim 1, wherein said external circuit is detachably connected to said flow channel.

16. A device in accordance with claim 1, wherein said flow channel comprises a respiration tube and said external circuit is arranged at a spaced location from said respiration tube.

17. A device in accordance with claim 16, further comprising a second internal circuit arranged in said respiration tube at a spaced location from said internal circuit, said second internal circuit being designed for contactless, inductive coupling with said external circuit for energy supply and reading.

18. A volume flow measuring device comprising:

a channel structure defining a fluid flow channel, said channel structure defining an interior fluid flow region and an exterior;

a sensor element comprising an internal circuit arranged within said flow channel interior;

an external circuit arranged at the exterior of said flow channel, said external circuit providing contactless inductive coupling with said internal circuit for supplying said internal circuit with energy and for sensing changes in inductive coupling of said internal circuit with said external circuit corresponding to changes in fluid flow in said flow channel.

19. A device in accordance with claim 18, wherein said sensor element comprises a hot wire having a temperature-dependent resistance connected to a first inductive element and a first capacitive element to form an oscillatory circuit and said external circuit senses changes in said oscillatory circuit due to changes in resistance of said temperature-dependent resistance caused by changes in volume flow.

20. A device in accordance with claim 18, further comprising;

a heating element arranged in said flow channel;

a flow resistance arranged in said flow channel between said heating element and said internal circuit, said heating element and said flow resistance being arranged in a same cross sectional area of said flow channel.