TRANSIT TIME ULTRASONIC FLOW MEASUREMENT

• US 20090143673A1
• Filed: 11/28/2008
• Published: 06/04/2009
• Est. Priority Date: 11/30/2007
• Status: Abandoned Application

• Current Assignee: Transonic Systems, Inc. (Measurement Innovations Corp.)
• Original Assignee: Transonic Systems, Inc. (Measurement Innovations Corp.)
• Inventors: McKee, Bruce, Drost, Cornelis J., Lutkins, Kevin, Shkarlet, Yuri M.
• Application Number:
  US12/325,096
• Publication Number:
  US 20090143673A1
• Time in Patent Office: Days
• US Class Current: 600/437
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 8/485 involving measuring strain or elastic properties
• CPC Class Codes: G01F 1/662 Constructional details
• CPC Class Codes: G01F 1/667 Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
• CPC Class Codes: G01F 25/10 of flowmeters

Abstract

A transcutaneous energy transfer system with subcutaneous non coupled coils is used to transmit power and signals to an implanted biological support device or sensor, such as a flow sensor for measuring relatively low flow rates, such as hydrocephalic shunt flow. The flow sensor is configured to convert a shear wave generated by a transducer to a longitudinal wave at the interface of a signal pathway and the flow, wherein the longitudinal wave travels parallel to the flow and exits a flow channel to convert to a shear wave which intersects a second transducer. The transcutaneous energy transfer employs a pair of inductive coupling coils, wherein the coils are disposed in zero coupling orientation which can include a perpendicular orientation of corresponding coil axes.

Claims

1. An implantable sensor assembly comprising:

(a) an implantable housing;

(b) a first internal coil retained within the housing;

(c) a second internal coil retained within the housing, the second internal coil being in a zero mutual inductance orientation relative to the first internal coil; and

(d) a sensor connected to the housing and electrically coupled to at least one of the first internal coil and the second internal coil.

2. The implantable sensor of claim 1, wherein the sensor includes a first transducer and a second transducer, the first transducer electrically connected to the first internal coil and the second transducer electrically connected to the second internal coil.

3. The implantable sensor of claim 1, wherein the sensor is an ultrasonic flow sensor.

4. The implantable sensor of claim 3, wherein the ultrasonic flow sensor includes a flow channel having a linear section bounded by an inlet bend and an outlet bend.

5. The implantable sensor of claim 3, wherein the ultrasonic flow sensor includes a shear wave transducer.

6. The implantable sensor of claim 1, wherein the first internal coil has a first coil axis and the second internal coil has a second coil axis, the first coil axis being perpendicular to the second coil axis.

7. The implantable sensor of claim 1, wherein the first coil axis intersects the second coil axis.

8. The implantable sensor of claim 1, wherein at least one of the first internal coil, the second internal coil, the first external coil and the second external coil includes a high magnetic permeability core.

9. The implantable sensor of claim 1, wherein each of the first internal coil and the second internal coil includes a plurality of coplanar windings.

10. A method of transcutaneously transferring power, the method comprising:

(a) subcutaneously locating a first internal coil and a second internal coil, the first internal coil being oriented in a zero coupling orientation with respect to the second internal coil; and

(b) inductively coupling a first external coil with the first internal coil.

11. The method of claim 10, further comprising electrically powering an implantable sensor from at least one of the first internal coil and the second internal coil.

12. The method of claim 10, further comprising connecting one of the first internal coil and the second internal coil to a subcutaneous sensor.

13. The method of claim 10, further comprising aligning a first coil axis defined by the first internal coil perpendicular to a second axis defined by the second internal coil.

14. The method of claim 10, further comprising defining a first coil axis by the first internal coil and a second coil axis by the second internal coil and disposing a first external axis of a first external coil parallel to the first coil axis.

15. The method of claim 10, further comprising simultaneously passing a current though the first internal coil and the second internal coil.

16. A transcutaneous energy transfer assembly comprising:

(a) an external casing retaining a first external coil and a second external coil, the first external coil disposed in a zero coupling effect orientation relative to the second external coil; and

(b) an implantable housing retaining a first internal coil and a second internal coil, the first internal coil disposed in the zero coupling effect orientation relative to the second internal coil.

17. The assembly of claim 16, further comprising a sensor at least partially retained within the implantable housing, the sensor electrically connected to at least one of the first internal coil and the second internal coil.

18. The assembly of claim 16, wherein the a first internal coil has a first coil axis, the second internal coil has a second coil axis and the first coil axis is perpendicular to the second coil axis.

19. The assembly of claim 18, wherein the first internal coil is spaced from the second internal coil, and the first coil axis is perpendicular to the second coil axis.

20. The assembly of claim 16, wherein the first internal coil and the second internal coil are nested.

21. The assembly of claim 16, further comprising a subcutaneous device electrically connected to one of the first internal coil and the second internal coil.

22. The assembly of claim 16, wherein the implantable housing, the first internal coil and the second internal coil are compatible with magnetic resonance imaging.

23. A method of transcutaneously powering a subcutaneous device, the method comprising:

(a) subcutaneously locating a subcutaneous device, a first internal coil and a second internal coil, the first internal coil disposed in a zero mutual inductance orientation relative to the second internal coil;

(b) inductively coupling a first external coil with the first internal coil, and a second external coil with the second internal coil; and

(c) energizing the subcutaneous device from one of the first internal coil and the second internal coil.

24. The method of claim 23, further comprising aligning the first external coil parallel to the first internal coil.

25. The method of claim 23, further comprising employing one of a biological support device and a sensor as the subcutaneous device.

26. The method of claim 23, further comprising simultaneously passing a current though the first internal coil and the second internal coil.

27. A flow sensor comprising:

(a) a housing formed of a first material, the housing defining a flow channel having a linear section bounded by a first bend and a second bend, the first material of the housing forming a first signal pathway adjacent the first bend and a second signal pathway adjacent the second bend;

(c) a first transducer adjacent the first signal pathway; and

(d) a second transducer adjacent the second signal pathway.

28. The flow sensor of claim 27, wherein the first transducer is directly connected to the first signal pathway.

29. The flow sensor of claim 27, wherein the second transducer is directly connected to the second signal pathway.

30. The flow sensor of claim 27, wherein the first transducer is acoustically coupled to the first signal pathway.

31. The flow sensor of claim 27, wherein the second transducer is acoustically coupled to the second signal pathway.

32. The flow sensor of claim 27, wherein the first transducer produces a shear wave to pass along the first signal pathway, the first signal pathway selected to refract the shear wave into a fluid flow in the flow channel and convert the shear wave to a longitudinal wave to propagate along the linear section and refract into the second signal pathway to form a refracted shear wave in the second signal pathway.

33. The flow sensor of claim 27, wherein the second transducer is located to intersect the refracted shear wave passing though the second signal pathway.

34. The flow sensor of claim 27, wherein at least one of the first and the second transducer generates signals corresponding to at least one of a velocity of a fluid flow in the flow channel and a density of the fluid.

35. The flow sensor of claim 27, wherein at least one of the first and the second transducer generates signals corresponding to at least one of a velocity of a fluid flow in the flow channel and a temperature of the fluid.

36. An subcutaneous assembly comprising:

(a) a first subcutaneous housing;

(b) one of a sensor and a biological support device at least partially retained within the first subcutaneous housing;

(c) a second subcutaneous housing;

(d) at least one coupling coil at least partially retained with the second subcutaneous housing; and

(e) a subcutaneous conductor electrically connecting the biological device and the one coupling coil.

37. The subcutaneous assembly of claim 36, further comprising a second coupling coil in the first subcutaneous housing.

38. The subcutaneous assembly of claim 37, wherein the second coupling coil is in a zero mutual inductance orientation relative to the one coupling coil.

39. The subcutaneous assembly of claim 36, wherein the sensor is a flow sensor.

40. The subcutaneous assembly of claim 36, wherein the sensor is an ultrasonic transit time flow sensor.